https://www.express.co.uk/entertainm...-date-backlash
Just a rumor really (and wouldn't this technically make the "second part" Episode 10?). Curiously, fans on some forums were wondering if this was a possibility all the way back to 2016, with discussion of course becoming more prevalent in the last few months due to Infinity War's approach.
Also, although at least three TV shows are in the works (Live-action, Resistance and Clone Wars revival), there hasn't been any announcement of a Star Wars film for 2020, and "splitting" 9 could perhaps work towards that.
Wouldn't be the first idea to have a trilogy end on a cliffhanger (Don't really count ROTS's ending since it was known what was going to happen) In some early stages, ROTJ was intended to have a cliffhanger and continue the story with some characters dying but Luke still on his quest to become a Jedi and overthrow the Empire. (However, Lucas decided to compress things into ROTJ) There was also of course one ending idea that would reveal Luke actually went to the dark side and put Vader's helmet on his own head....