We just returned from Oahu last night. I agree with the poster who said to take advantage of being up early to get to the places that fill up quickly. Diamond Head was very hot by 9am and the Hanauma Bay parking lot was also filled by then. The Arizona Memorial was packed and out of tickets by 1pm so that is another good place to go earlyl We were up between 4 and 5am for the first few days of our trip. Luckily we were right by a 24hour
Dennys for breakfast.

Just came back today. Had a bit of a hard time adjusting as we got there at 4:00pm and it was 9:00pm for us back home.

Since you are coming in at 11:30, I recommend taking 1 Tylenol PM right when you get to the hotel. This will help you sleep and feel rested. I did this for the first 3 days and felt good when I woke up.