Rian Johnson is the director for the upcoming Star Wars: The Last Jedi, and he has also contributed to the script of the movie. Colin Trevorrow will direct and write Star Wars Episode IX, but he didn’t get any help from Johnson.
A fan had asked Johnson on Twitter about this, and he said:
@mattpeto That's old info, I haven't been involved in writing IX.
— Rian Johnson (@rianjohnson) April 24, 2017
Star Wars: The Last Jedi comes out on Dec. 15, but Star Wars Episode IX is set for a release on May 24, 2019.