First I want to share some things that I noticed in the promotional picture.

The picture is cut or divided in several places.
Most noticeable is the division between light and darkness. Shown in green. The upper part of the picture is clearly the light side, while the lower part is the dark side. But what is interesting, is the fact that Kylo Ren is not fully in the dark part of the picture, he is in between, which to me means that he is still struggling between the light and dark sides of the Force.
Four of the knights of Ren are also partly in the light part of the picture. Some episode IX fanfics have the knights of Ren as villains, and after Ben is redeemed, he has to fight them.
I don't mind this, and I have even done it in some of my stories. But one of my best friends, Winter Wolf, and I have discussed the fact that if they are some of Luke's students, then they might be a bunch of teenagers. We also don't think that they are loyal to Snoke or to the Dark Side, but to Ben. So, if Ben turns to the Light Side, or joins the Resistance, some of his knights might fallow him.
Notice (circled in red) that Rey is the source of the Light. She is the one who is keeping Ben from being in total darkness. She is the one pulling him into the light.

The picture is divided in a second place, shown in yellow. Kylo Ren's lightsaber goes all the way across the picture. It almost looks as if he is protecting not only Rey, but all of the Resistance from the First Order. But not just Rey and the Resistance, but also his knights.
Both Rey and Ben have been scarred, both on the outside- Ben on his face and Rey on her arm- and on the inside, where it is harder to heal.
In the Last Jedi their scars were visible, both inside and out. But in the Last Jedi, they were mostly only around each other, and they didn't mind showing their scars around each other, because they excepted each other no matter what. But in Episode IX, they are around other people, so they hide their scars. Kylo Ren's behind a mask, and Rey's behind the leather band. But it is really the emotional scars that they are really hiding.
I love Rey's new outfit, it is solid white, while Kylo Ren's is solid black. It shows how opposite they really are. It also symbolizes that he is an embodiment of the Dark Side, while she is an embodiment of the Light Side. And that if the Force is brought together, it will be done by them.
This is my digital art of Rey and Ben from Episode IX.

Ben's outfit might not be accurate, since I have not yet found a photo of his outfit from Episode IX. So, I just drew his outfit from The Last Jedi. I also used the same pose as The Last Jedi promotional photo. I looked at it for reference to draw this picture.
I drew Rey in her white outfit in a black background, and Ben wearing black on a white background, to show how opposite they are. But it also shows how much they are like ying and yang. Completely opposite, but balancing one another out.
I hope you like it. I wanted to be one of the first to make Reylo fan art of Rey's outfit from Episode IX.
Date made: April 1, 2019
Date published:

(And yes, I have been working on this chapter since April 1st. I spent April fool's day drawing the picture and started writing on the 2nd.)