We were really excited when we heard that Rian Johnson would not only be directing Star Wars: The Last Jedi, but had also signed on to write a treatment for Episode IX.
Before, the case was that Johnson would write a treatment that would act as the foundation for Colin Trevorrow (who is directing Episode IX) and screenwriter Derek Connolly to then build a script from, but now it looks like Trevorrow and Connolly are working on it on their own.
I doubt that this has anything to do with any bad blood between Johnson and the studio, or Johnson and Trevorrow.
Episode IX is Trevorrow and Connolly’s boat now, so let’s hope they can end the new trilogy the way it deserves.