I've never had a plott hound but I know a few, they come into the humane society I volunteer at surprisingly quite a bit. I would neuter him at this age. Its pretty outdated to wait until they are six months, maybe find a different vet just for this procedure. Since the first three months or so of his life he probably wasn't socialized well it will take some time for him to learn. This is actually one of the best hounds you can get for a companion and family pet as long as they are trained and socialized early. They are couragous and pups will have no problem teasing bigger dogs and getting themselves into trouble. The best way to tell temperment is through the parents, but train and socialize all you can and the pup should turn out. Maybe you should find a bigger dog at the park that is willing to gently but firmly put a pup in its place. Anyway, he's a teenager, good luck.