On Caribbean Princess, the pools/spas were not open 24/7 as they had been on the Grand, Golden, Coral and Star when we went on them. The hours varied by pool, but I don't remember the hours. The pool with MUTS closed earlier, around 5:30 or so I think.
The entertainment wasn't as good on Caribbean Princess as we've experienced on the other ships. Not horrible, just not as good. Although the pool band was excellent. I think they were called Vibz.