I'm not sure I understand your question, but are you renting a car in Kahului and returning it in Lahaina? Or will you return the rental in Kahului and not have a rental in Lahaina?

Sorry, but maybe someone can help me understand?

In Lahaina, there's Front Street, you can walk around there for a few hours. Do lunch and shop shop shop. There's a variety of boutiques, stores, restaurants, bars , art galleries. Have a great time...

Lahaina is about a 30-40 minute drive from Kahului....

You can rent a car near lahaina if that is where your ship tenders, or if tendered in Kahului, rent a car at the airport. The closet rental agency to Lahaina is Kapalua Airport about 10 minute north of Lahaina.

It sounds like bhami is doing an NCL cruise--one night in Kahului, one in Lahaina. I know you can grab a car rental shuttle at Kahului. I assumed that on boat day in Lahaina the Ka`anapali agencies do the same.

You can spend the day in Lahaina, There is a walking tour of historic sites, but unless you are really up for endless tee-shirt shopping, it might wear on you after a while. You can catch a shuttle that will take you to Ka`anapali to Whaler's Village, leaving from the Wharf Center on Front Street, by the Banyan Tree. You can always get in some beach time at Ka`anapali.