My tomatoes top seven ft all of the time. I do not prune, but I do have them in cages. When they get to the top of the cage and get heavy enough they will start to cascade over, but most of the time they don't get much taller than eight feet or so unless it is the wild ones. They will root their stems in the ground as they ramble and then the plants can get pretty long.
Happy gardening in Hawaii. Gardens are where people grow.