If you are worried about security, you could try bougainvillea. That is a pain to trim though. Hibiscus and tiare are nice, full bushes with pretty flowers but I don't think they get up to 10 feet. The community garden in Pearl City has a large display of croatans, I seem to remember them being thick and tall, and I know that area gets intense heat. Panax are popular for creating a fence, but I'm not a fan of the look. If you are willing to build a trellis/support system you could grow a vine thru it like lilikoi or stephanotus. Those are my suggestions, but I like lots of color.

Thank you, I'll take a look at the community garden in Pearl City.

Perhaps a variegated Hao? We have two, and they grow to a very dense thicket, maybe 20 feet high, or so. But you can keep them trimmed into a tree shape, if you want. We also have a Buddha-belly bamboo which is a bit of a monster, but it has gotten big and thick -- a good barrier.

Put up some pipes with chicken wire and plant passion fruit they get about 3 ft. thick and any length you want, fast growing and produce good fruits I have one and my wife makes passion fruit pies, cookies, cakes, and drinks most of all they are easy to take care off they trim easy