My advice would be to figure out how to do one boat trip, to the Island of Lanai, to see the Cathedrals. Very close to you and I can’t recommend them more highly is Lahaina Divers. If you did that and then did a shore dive at Black Rock reef in Kaanapali (enter at Sheraton’s beach) that would be a pretty complete trip in my mind. But the shore dive won’t even come close to the Lanai and the Cathedrals. Check out their video: http://www.lahainadivers.com/content/lanai-scuba-diving-with-lahaina-divers
Two dives for $129 is well worth it. Have a blast!