dev-util/android-tools-9.0.0_p3-r1 provides an adb version 40.
The latest android studio (4.0.0+) uses adb client that is version 41, so it fails due to version mismatch
Steps to Reproduce:
1. Install android-studio 18.104.22.168.193.6514223
2. Attempt to use adb within Android Studio (e.g. adb start-server)
3. Should get error: adb server version (41) doesn't match this client (40); killing...
See Steps to Reproduce for details.
adb should not fail and no mismatch error.
android-tools needs to be upgraded? to provide an adb that is version 41.
Android studio v4 ebuild is awaiting version bump, see: https://bugs.gentoo.org/727430. In that bug, I've added a sample ebuild that can install Android studio v4.
This is not a bug, it's the intended behavior.
Close this, what you want is a bump request like Bug #707568 (or whatever the equivalent android 10 version is these days).