"Clubhouse" is the best form to use. It's a single thing. We use the hyphen to tie together words (temporarily), and eventually we drop the hyphen and make the two words a single word, once we are familiar with the expression. Eg. "midday" used to be spelt "mid-day". This is seeing the language in its evolution.

"clubhouse"

Yes and it all means the same thing. Example if you belong to a golf club, you might say to another golfer, "I'll see you at the clubhouse after my game".