We really enjoyed just wandering around in this port.
We took the advice of a previous cruiser and walked a few blocks inland from the pier and caught the A express bus. We got off at Pearl Harbor and walked to the visitor center and purchased tickets ($24 each) for the USS Missouri. We chose to look around ourselves instead of a guided tour.
The bus ride was $4 round trip from near the pier.
You could also go to the Arizona Memorial but make sure you get there early. It's free but first come first served. We had done this in the past and felt we should leave the Arizona for those who have not.
There were many small shops and outdoor vendors near the pier and we found most of the things that we wanted at reasonable prices.