First off, Roll Tide! So glad to have A&M in the SEC; y’all have been THE best fans!! ( Plus my seats are near the visitor band and the Yell Crew always end up at our concession stand LOL and they’ve been so nice to my kids)
Anyway, just my take, but unless you just really hate driving, we found it super easy to get ourselves anyplace we wanted to go, with the freedom to change on the fly. Oahu (and the other islands) is small and easy to navigate; we had no issues at all.
That said, assuming everyone is fully-able physically, I think you should do Diamond Head. I know folks say the Tantalus lookout is a better view (we didn’t go there), but standing up on the edge of the crater and looking down into it, plus along the coast, was very cool. (We also met two sets of Bama folks up there too, oddly enough.) Do go early, though, as parking can be tough.
Another thing some say is too touristy is Hanauma Bay. We, however, count it as one of the top three things we did out of 4 islands. Even when it’s busy, the lagoon is huge and we felt like we were nearly alone in the water. Just gorgeous; we stayed until the last tram up the hill was leaving (cuz I was NOT walking up after climbing DH and snorkeling the rest of the day!!).
Pearl Harbor, of course, was a must for us. If you’re craving “home cooking”—or like me, some dang sweet tea—Dixie BBQ is like a mile from the memorial and has legit BBQ, plus fried okra.
We skipped the Dole Plantation because we got our Dole Whip fix at Aulani and really saw no other reason to go. We drove by it on the way to the north shore, where we also enjoyed snorkeling at Sharks Cove )but not as much as HBay. The rocks are very sharp there, so be careful if you go. We stopped for lemonade at Wow Wow in Haleiwa and it was delicious. Haleiwa town was cute and I wish I’d had more time to shop on all the islands, but I just couldn’t prioritize it over all the active things we did.
I also didn’t get much beach time on Oahu for any of the gentler wave beaches (Aulani lagoon is like a bathtub lol), so I’d like to do some more of those next time, like Kailua.
Our friends (and many here) really enjoyed Kualoa Ranch, so we’d probably do some horseback riding there if we go to Oahu again. Kids really enjoyed it more than I expected when we went riding last summer; we have horses but none are safe enough for them, so they never get to ride!! (Talk to my husband—I tried to get him to buy them some better horses!!)
So that’s WAY more than you asked!! Happy to answer anything I can.