I've been able to use the compilation successfully a few times, but now it seems to just always hang. I've looked up similar issues and they all seem to point to some timeout due to fsc. There is even an argument you can pass in 2.9. While it's possible I'm being hit by this issue, it doesn't seem to be caused by a timeout since in my case, I hit it right away. I'm completely unable to use the compilation server at all.
Some people mentioned starting fsc manually, but whenever I do that, I end up with a second instance. I can see 2 fsc instances running, the one from the plugin and the one I started manually.