The Force Awakens was more of Han Solo’s movie, while The Last Jedi will be Skywalker’s movie, and it was assumed, apparently even by Fisher, that Star Wars 9 would be Leia’s movie.
This will be the first Star Wars episodic movie to open in May since Return of the Jedi in May of 1983.
Fisher’s death didn’t change anything on The Last Jedi, but it turned out to have a massive effect on Episode IX.
Star Wars 9 will officially begin shooting in January 2018 under the direction of Colin Trevorrow.