I'm not a bed at 9:00 person either...except...on our Alaskan cruise the sun rose at 4-4:30 and we DID get up for sunrise. There are plenty who are still tooling around after 9, but it's a different cruise experience overall. More casual dress in the evenings, tends to be an older passenger, the pools are (usually) not usable so parties by the pool do not exist, most events are indoors - it gets COLD outside at night. We found dancing at night but nothing like the Mexico/Caribbean cruises.
All that said...we LOVED our Alaska cruise and hope we can go again!