Do you have a start9? - there is an early StartOS package: https://github.com/horologger/albyhub-startos (you can download the .s9pk file from here if you're logged in at github: https://github.com/horologger/albyhub-startos )
By running Albyhub on my Start9 or on a standalone RPi, will this reveal my IP to Alby and/or liquidity provider, or does it run behind Tor?
When you do requests to services like a liquidity provider or Alby it might see your IP if you don't put it behind a VPN or similar - just like any other resource that you load. afaik the LSPs do not offer Tor hidden services (at least not all).