On our December cruise, we had 8:00 breakfast and hung around the Promenade Lounge (on the Wonder) after that until about 9:30 when the final debarkation group was called. (Our shuttle wasn't coming until 10:30, so we had time to kill and the lounge made a comfortable place to wait.)
Guest Services and the main dining rooms were pretty much the only thing open. (I think there were some Shutters people available for questions, too.)