It's installed by default but not running by default. So the only resource it consumes is a small amount of disk space, plus one socket so it autostarts if you try to use it (by connecting to example.com:8888 or whatever it is).
If it's listening on a socket and spins up on a request sent to the port that socket is bound on, for all intents and purposes, it is running and enabled. This is the same behavior as old inetd-based servers.
Correct, if you try to open http://<hostname>:9090/ it will get automatically started. I'm not concerned about the resources it uses, I just don't like having services that I don't use installed and listening on ports in minimal install, especially on servers.
