If you got him from the St. Pete SPCA, he is likely one of the infamous Holland dogs (30 plus basenjis rescued last year in Hillsborough county) and they are very human-shy and unsocialized, but with some work they turn out great, we know of 2 who are several years old now who are great dogs.
6 1/2 months is rough age, with chewing and hard play biting, even for home raised, socialized pups! When we have had pups, we cried out when they would bite too hard, startle them then redirect them. Also remember, a tired basenji pup is a good (or at least tolerable) basenji! Good luck. We have a friend in Safety Harbor who has a trainer she likes, and has worked with her 2 basenjis, one of whom was pretty unsocialized when she rescued her.