It is working here, but not at boot. I need to navigate to the plugin and disable/enable it. When I do that it will show up in spotify but not before that, doesn't seem to autostart on boot? I was on an old build (manually installed), uninstalled that one and got the one from the repo's.
Another strange issue, I have auto screen off after 5 mins, this kills the music while it is connected through SPDIF not HDMI.