Can we store our luggage after our cruise so we can spend time in Sfo before returning home rather than wait in the airport for 4 hours.

Ask one of the passport checkers what the best course of action would be.

No

Due to federal security regulations, there is no luggage storage at the San Francisco cruise terminals at Pier 27 and Pier 35. Luggage storage is available at the California Welcome Center at PIER 39, which is located approximately 0.4 miles from the terminals. Open 0900-1900hrs 7 days except Thanksgiving and Christmas