GNU/Linux Ubuntu 20.04 Installing Android 9.0 Emulator Guide
The linked tutorial shows you step-by-step How to Install Android 9.0 Pie Emulator Virtual Machine in GNU+Linux Ubuntu 20.04 Focal LTS desktop.
And this is the easiest way to dispose for Free of a nicely performing Android 9.0 Emulator on Ubuntu for running & testing Android Apps on GNU/Linux.

Android 9.0 Emulator Ubuntu 20.04 VirtualBox VM Setup