Shouldn't they be already shooting the movie though?
I was actually wondering this myself. Going off Wikipedia...
The Force Awakens- Started shooting 19 months before release date
Rogue One- Started shooting 16 months before release date
The Last Jedi- Starting shooting 22 months before release date (should be noted this was due to location availability in Ireland)
Han Solo- Started shooting 17 months before release date
We are roughly 20 months before Episode IX's release date.
EDIT: Should be mentioned that Episode VIII was supposed to come out May of this year but the date was changed to December. It has been rumored Episode IX and maybe even Han Solo would do so as well (both are slated for May of 2019 and 2018 respectively).