The Cultural Center is so much more than just a Luau. To go there and just do their Luau would be a waste. Plan a whole day. Come across the island and stop at Dole plantation and drive the north shore past all the famous surfing beaches in the morning. Get to the cultural center at noon when it opens. Book an Ambassador package and pick the Luau as your dining option. For the first 5 hours you will get a small group escorted tour of the center and it's "countries" . You will see all the major exhibitions and shows. You will get a shell lei, a video . Then on to the luau. Flower Lays, Food and drinks (no alcohol here ), music and entertainment. After dinner you go to the outdoor (covered ) theatrefor the spectacular Polynesian show. Your package gets you special drinks and desserts. All over at about 10 pm. Drive back to Honolulu via the east coast road for a change of pace. Book on line in advance and you will end up with first or second row dead center seats for the evening show.
This will end up being the best day of your vacation.