We didn't go to Aulani, but my 13 year old LOVED Maui and the Big Island.
The question is, are you going to sit on your butt at the beach at Aulani? and will your son enjoy that? We took ours on a whale watching cruise, went and saw the volcano, took him surfing twice (he wasn't at all bored with that), saw the whaling museum in Lahaina, went snorkeling, went to a luau. And there was a ton of stuff we didn't do, like the Hana road.
Much of this is available in Oahu (no active volcanos, whales are seasonal in Hawaii, and the scenery is, of course, island dependent), although you'll need a car. Plus Oahu has the Pearl Harbor memorial.
As for sitting on his butt, my son also enjoyed - at 12 - an all inclusive in Mexico which involved a lot of mom and dad sitting by the pool reading while he and his sister hung in the pool or at the beach. Fourteen is getting old enough to enjoy the beach scenery that appears in Hawaii or Mexico in small bikinis.