NCL supplies service for a fee for people to be taken to airport but not just luggage. I think that it would be a security issue for just sending luggage
You could look at doing an excursion that has drop off at the airport through NCL
And there is luggage storage at the cruise terminal but luggage must be pickup by 5 pm. I think its like $5 per bag.
There are also companies that you can make arrangements with to take your luggage to the airport. Here is a link;
https://www.google.ca/search?q=is there is luggage storage at the cruise terminal in Honolulu Oahu&rlz=1C1CHBD_enCA779CA779&oq=is+there++is+luggage+storage+at+the+cruise+terminal+in+Honolululu&aqs=chrome..69i57.28813j0j8&sourceid=chrome&ie=UTF-8&npsic=0&rflfq=1&rlha=0&rllag=21305932,-157872792,5753&tbm=lcl&rldimm=17498621273139293031&lqi=CkNpcyB0aGVyZSBpcyBsdWdnYWdlIHN0b3JhZ2UgYXQgdGhlIGNydWlzZSB0ZXJtaW5hbCBpbiBIb25vbHVsdSBPYWh1SLHStsbHkICACFo8CiZsdWdnYWdlIHN0b3JhZ2UgYXQgdGhlIGNydWlzZSB0ZXJtaW5hbBAAEAEQAhADEAQQBRgEGAUYBxgI&ved=2ahUKEwj_1vGw9Y7iAhXtYd8KHcOhAF8QvS4wAHoECAoQIQ&rldoc=1&tbs=lrf:!2m1!1e2!2m1!1e3!3sIAE,lf:1,lf_ui:2#rlfi=hd:;si:17498621273139293031,l,CkNpcyB0aGVyZSBpcyBsdWdnYWdlIHN0b3JhZ2UgYXQgdGhlIGNydWlzZSB0ZXJtaW5hbCBpbiBIb25vbHVsdSBPYWh1SLHStsbHkICACFo8CiZsdWdnYWdlIHN0b3JhZ2UgYXQgdGhlIGNydWlzZSB0ZXJtaW5hbBAAEAEQAhADEAQQBRgEGAUYBxgI;mv:!1m2!1d21.3358608!2d-157.8190761!2m2!1d21.272612000000002!2d-157.9310735;tbs:lrf:!2m1!1e2!2m1!1e3!3sIAE,lf:1,lf_ui:2
look to left of page. You may also want to contact the cruise terminal and make sure they still hold luggage. they are at top of page in the link
Can't answer for Uber but there are thousands of cabs in Honolulu
As for sight seeing there is lot to see around the cruise terminal. You ʻIolani Palace just across the street from pier Aloha Tower, China town, you located right in the Financial District which is closed up on Sat so you can stroll around to see the older buildings. Murphy's Bar and Grill which is the first bar allowed in Hawaii and has great food.
You can easily kill time around the cruise terminal area. As for the airport you will have two security area's to clear one is and agricultural check of your bags (scanner)an then the usual security check in. The airport also has a lovely outdoor Asian garden located by the food court with ponds and benches grab a coffee and go sit outside.
Check in be fairly smooth as there is never a lot of flight going at the same time.
Lastly you'll have a great cruise and make the most of all the islands, we have done this cruise many many times.