So, at the end of the trailer, we hear an evil laugh. Which I knew had to be either Snoke or Palpatine. But as a fan of the Lord of the Rings, I know Snoke's voice, (he was played by the same actor who played as Gollum.) And that wasn't his voice.
Here are some memes that describe my reaction to the Palpatine laugh at the end of the trailer:

And then:

After watching the trailer, I was trying to figure out why Palpatine's laugh would be at the end of the it.
I came up with several possibilities.
It could be Snoke, and he just happened to sound like Palpatine for some reason.
Maybe it's a new villain
Maybe they just put the laugh at the end of the trailer to trick us and he's not even in the movie.
But then who do I see on the cast list:

There can be no mistake. Palpatine will be in Episode IX.
Either that or someone is going really far to trick us. And I seriously doubt that they would, because then they would have to face an army of Star Wars fans.

Part of me likes this, but part of doesn't. I can see both good and bad aspects of it, it all depends on how it is done.

Things I like about it:
1. It would tie in both the prequels and the originals, if it is done right.
2. Ben Solo/Kylo Ren can't be the major villain of the story, he has too big of fan base, he's not a hatable character, and the fans have already seen that he has good in him. I think after The Last Jedi most fans are rooting for his redemption, in stead of rooting for him to be destroyed. He has already shown more signs that there is still good in him then Darth Vader had in the second movie of the original trilogy, in fact he came very close to being like Darth Vader in the third movie, the fans are just going to spend Episode IX waiting for him to be redeemed and that would ruin the whole point of a major villain. The fans might start rooting for him instead of the heroes (except for Rey). Personally in the Force Awakens, when he fought Finn, it took everything in my power not to root for Kylo Ren, at least not outwardly. But after the Last Jedi, I won't be able to keep myself from rooting for him, except if he was fighting Rey, then I would be torn apart.
3. Ben Solo/ Kylo Ren is too likable of a character to be the main villain. He really has the potential to bring balance to the Force, because he has both the light side and the dark side in him. But he also has the potential to bring balance to the Star Wars fandom, as he has elements of both the prequels and the originals in his character. He is also the only new character that is directly connected to the old characters. He is apart of both Anakin and Padme, and Han Solo and Leia. But he is also a part of Luke Skywalker, and he even carries the memory Obi Wan Kenobi/ Old Ben Kenobi since he is named after him. Of the new characters, he is really the only tie to the past. And even though he said to let the past die, no one wants to do that, and he is the past, we don't want him to die.
4. If Ben was the main villain it would either make his redemption too easy or too hard. It would be too hard because he would have to wait to the last moment to be redeemed, otherwise there would be no major villain. But it would also be too easy for him, as he would have no one to face, maybe the first order.
I have seen some say that Hux will be the major villain, but I just didn't really feel that he was a worthy opponent for both Rey and Ben.

Things I don't like about it.
1. I think it is a bit odd to create a villain that has as much potential as Snoke, then just toss him in the wind as if he never existed, then resurrect an old villain to replace him. But there are ways they can do the storyline that could fix this.
(1. Explain who Snoke was.
(2. Perhaps make Snoke Be in league with Palpatine, like they had been working together all along. Regardless Snoke has to be tied into Palpatine somehow for this to make sense.

2. I have to agree with my friend Winter Wolf on this one: Anakin killing Palpatine, his evil master was his redemption, it was Anakin's triumph. Resurrecting Palpatine, or having him survive undoes all the good that Anakin did, the balance he created has already been destroyed and now they bring back Palpatine who Anakin died destroying. It makes his sacrifice seem pointless. He redeemed himself and saved his son, he finally achieved his destiny and brought balance to the Force, and defeated the villain who had turned him to the Dark Side. Already the balance has been taken away, which was understandable because the balance wasn't true. But now they take away his victory against Palpatine? And they blame him for Ben turning to the Dark Side, when it was really Snoke's fault, (and maybe even Palpatine's now that we know he is apparently not dead.) But what is left for Anakin? The only way to have Palpatine in Episode IX and not completely destroy Anakin's victory over him is to have Anakin's Force ghost and let him play some small part in Palpatine's defeat. Perhaps he actually fights Palpatine. I mean Obi Wan said that if Darth Vader struck him down he would become more powerful than he could imagine, yet Force ghosts don't do much. It would be cool to see Anakin's Force ghost actually fight Palpatine, and maybe even finally bring balance to the Force with the help of Rey and Ben. Or perhaps he plays a smaller but equally important role such as helping bring Ben back, or helping Rey become a stronger force user.

These are some ideas of what his role in Episode IX could be

One
J.J. Abrams said that the heroes would have to face the ultimate evil in Episode IX. Kylo Ren is certainly not the ultimate evil, he has been abused by someone who was far more evil and he triumphed over him to save Rey. But Hux doesn't seem like the ultimate evil either.
But is Palpatine the ultimate evil? I just commented on Star Wars book that Snoke is more evil than Palpatine. And here's why:
1. Palpatine was cruel and evil, but I never saw him physically or emotionally abuse Anakin (even though he did lie to Anakin and say that he killed Padme, when he didn't) But we do see Snoke being both physically and emotionally abusive to Ben.
2. Palpatine didn't say that Anakin was weak because he was broken hearted over Padme's death, but Snoke mocked Ben for being broken hearted over his father's death.
3. Snoke constantly berates Ben saying that he's weak, or not good enough not strong enough. Saying that he's nothing like Darth Vader when he knows that he wants to be like him. Palpatine never said that Anakin was weak, he did the reverse fooled him into thinking that he needed Anakin, and that Anakin needed him. Palpatine controlled Anakin by becoming a father figure to him, which made him believe that he had to obey him and be loyal to him. But Snoke abused Ben into being loyal to him.
4. When Luke was brought before Palpatine, he gave him a chance to come to the Dark Side and join his father. But when Rey was brought before Snoke, he didn't even give her the opportunity to join him, and he knew that Ben cared about her.
5. Palpatine tried to kill Luke in front of his father who loved him. But Snoke knew that Ben cared about Rey and tried to force him into killing her. Snoke could have killed Rey easily. But instead he forces Ben to kill her so that he will have to live with the guilt of her death for the rest of his life, just like he has to with Han Solo.
So, Snoke is far more evil than Palpatine in my opinion, so why would Palpatine be called the ultimate evil, when Snoke is just as evil, if not more so?
Here's one theory that I came up with:
What if they're actually the same person?
This is just a thought, Palpatine was trained by Darth Plagueis, who could manipulate life. We don't know Palpatine's full power. What if Snoke was some kind of form that he created in order to control the galaxy without revealing that he was still alive.
This would also explain why he keeps comparing Ben to Darth Vader, and saying that he is not as good as Darth Vader. If he is Palpatine, (part of Palpatine) he would be constantly comparing this new Apprentice to his old one.
What if Snoke is Palpatine's revenge on Anakin?
What better way to get revenge on Anakin than to corrupt his grandson, who looks up to him and pull him to the Dark Side. And use Darth Vader's name to pull him further into the Dark Side and make Anakin feel like it's his fault.
Not only that, but if Snoke was the one behind Luke trying to kill Ben in his sleep, then he used the son that Anakin loved, the son who had saved him to pull his grandson to the Dark Side.
If Palpatine is connected to Snoke, then Palpatine is trying to get revenge on Anakin. He is taking out his anger towards Anakin on his heir, and that is why he is being so cruel to Ben. He isn't trying to punish Ben, he's trying to punish Anakin for turning on him and he's using his grandson to do so.

Two

Palpatine could be some kind of Force ghost who haunts the second Death Star where he died.
Regardless, I believe that Palpatine will be connected to the Death Star shown here. Which to me means that it is the second Death Star, where he died.
"Rey, Finn, Poe! Don't go in there!"

Three
Perhaps Palpatine's role in Episode IX is not as big as we are expecting. But would still be a very cool scene in Episode IX.
Maybe Rey goes into the second Death Star and sees a vision of Luke Skywalker saving Darth Vader, and Darth Vader defeating Palpatine and saving Luke. And it is this vision causes her to realize that she has to save Ben.
But perhaps it is the reverse. Perhaps Ben goes to the second Death Star and sees a vision of his grandfather, who he looks up to saving Luke and redeeming himself and he realizes that he has to do the same for Rey.

Four
I almost hate to even suggest this because it seems weird, and I've already written more than one chapter contradicting this. But it is a possibility, and I am trying to explore all possibilities for Palpatine in Episode IX.
Maybe Rey is related to Palpatine, or he manipulated the mediclorines to create her.

I dismissed this theory in my chapter discussing all of the theories about Rey's parents. But because he is going to be in Episode IX, I can't completely ignore, dismiss, or deny the possibility of this theory.
But why would he create her? It doesn't make sense to me.
However I will say that if this does happen in Episode IX, it won't be as big of contradiction to the Last Jedi as some theories.
If he used the mediclorines to create her, she could have been born to junk traders, just as Ben said, and he didn't see the fact that Palpatine was the one behind her birth. Or he did see it, but was trying to spare her by not telling her. He probably didn't want to tell Rey that she came from Darth Sidious who caused his grandmother to die and his grandfather to turn to the Dark Side and brought the galaxy into darkness. That would be something he would want to spare her from, just as Obi Wan wanted to spare Luke from the truth about his father.
Not that I'm saying this theory is true. Just that it's a possibility.

Finally just for laughs, here's an Episode IX title:

😂😂😂😂😂😂