Half day on Okinawa island

Hi
I have some time to spare on the day of my return to home. My flight leaves about 20:30 from intl terminal. Not sure what I could see on a half day or so in southern Okinawa island before going to Naha airport. I suppose being at the airport by 18:30 is fine.

I have seen the Shuri castle but thinking of the outskirts around Naha. If bus is fast enough.

Any suggestions?

This thread by a person in a similar situation might help.
https://www.japan-guide.com/forum/quereadisplay.html?0+161353

In short, you can rent a car or hire a taxi if you're not using public transportation. You can visit major war memorials that are unique to Okinawa, or stroll down Kokusai-dori, or visit the cozy village-like outdoor museum of Ryukyu-murai, spend hours at the Churaumi Aquarium, swim ..... you've got many options.