To be honest, if a userland application is capable of kernel panicking a phone, that's a bug in the kernel, not in the application.

There's also a bug in Android (official and LOS) which I've encountered many times related to location detection in certain always-on GPS apps, causing a systems freeze and a reboot. This sucks, but it's a bug with Android, not with the application itself.

The Android/LOS peeps should really take a look at this though. I don't expect this to be the only app that can cause this and with some severe bad luck the crash might even be exploitable.