If you are in the same stateroom, you don't pack up. If you are in a different stateroom, you pack up and then someone will move your bags for you.
You'll get a letter the night before giving you the procedure. I know some people on other cruises who were to meet in one of the lounges and then were escorted off, went through customs and then brought back up to check in. We were just told to disembark by about 9:15 am, clear customs and then go back up and check back in again. There were only 3 families including us so we were put into the concierge lounge in the port and then allowed back on at about 10:30. All we took off the ship was our iPads and bathing suits.
You can't go back to your stateroom yet but the Cove Café was open so we sat there for a bit with a couple of coffees and then went for an early lunch. We had thought to go into the pool but just ended up reading for a while.