I don't know if $DIS thought TLJ would do as well as TFA, but they made sure they were going to make as much, if not more, money off of it. Look at the things they pulled with movie theaters if you want evidence - **65%** of each ticket sale, minimum # of weeks in the top theater, etc. That doesn't say to me that the movie studio is confident in its product, it smells like a movie studio that's desperate.
Personally, I think they've damaged Ep9, and possibly the SW brand in general, with some of what they did in Ep8. I, for one, am not applauding Rian Johnson for the hot pile of garbage he made. Between the thousands of negative Joe Star-Wars-Fan reviews and Mark Hamill on record as saying, "This isn't my Luke Skywalker", you have a good reason to be wary. Disney's response? "It making money!" "It's selling merchandise!!!" It took all of 4 years of Disney/Iger's "guidance" to reduce nearly 40 years of Star Wars fandom into a pile of rubble. Bravo.
Call me a curmudgeon if you wish, but Disney doesn't have the Midas touch it used to have, and the only thing Disney is doing right these days movie-wise is letting Kevin Feige run the MCU. They've run Pirates into the ground. They're running Star Wars into the ground. Pixar is... well, Pixar, but we need to see what's going to happen with them and WDAS without Lasseter.