Are you planning to make your app working on Android 9.0 Pie ? There might be a few things you would to read first
Google says Android Pie SDK will be more Kotlin friendly. And guess what, it is not a new thing according to them. Maybe, it is time you think about Kotlin as well when you think about Android app development. There are lots of things you can take benefit of. Like Neural network API, app actions etc. There is also a new system navigation , multi-camera API which you can make use of
Good luck with making your apps work great on Android Pie.