The Polynesian Cultural Center is certainly a wonderful experience. It would take about an hour to get there from Honolulu so I'm wondering what they do as the center doesn't open up until noon. With some organization, (or a guide like you get if you book the Ambassador package) you can get to see many of the "islands" and the show or demonstration at each one. Another must do is the mid afternoon show on the water where dancers from all the islands perform on platformed canoes. This is a must for the video camera. At about 530 everyone is headed for the Lua and if your tour ends at
that time you'd probably have to be on a bus at about 4 or 430.
You are also missing two of the better "events" of the day, the luau and the VERY SPECTACULAR stage show done later at night.
Just a suggestion. If you have any time in Honolulu pre or post cruise, that would be a better time to experience the whole Cultural Center .