Hi there, I never found any facility that offered luggage storage, so we ended up booking a day room at the Best Western Plus about 10 minutes taxi/Uber from the pier. We left our bags there for the day, went sightseeing then came back to the room to have a shower before leaving for the airport. Your situation is a little different as you aren’t staying as long as we did, and their day room rate requires check out by 6pm. However, it doesn’t hurt to ask if they can offer you some kind of rate for the hours you need to be there for. Good luck.