I've talked to a couple of other Ren'py devs, and they told me they also had problems with their games not launching/shutting down randomly when played on Android. I think this might be a common-ish problem with .apks built in Ren'py, but I'm not 100% sure. The issue could also be that the VN isn't optimised very well for Android, which admittedy was a bit of an afterthought.
In any event, I'm glad you were able to get it working!