Do you really want your HA server to be an android device?
For most people, the server is a Raspberry Pi or something similar and the Android tablet is just the front end - you can access the server with a normal browser or download the companion app from Google Play.
If you do want to run Home Assistant on Android there’s a thread about it here (although it’s more than a year old):
Read the comments - a lot of people seem to think it’s a bad idea.