volumio can be run in a docker container (im assuming as there is something on docker hub) so it could be made into an add-on and run that way.
It is not necessary to use hass.io as the OS for raspberry.
I installed raspbian OS on it installed docker with hassio.
And there you can already put volumio. I also use in my project
still kodi, motion eye, and some more functionality.
You are welcome!