Depends on the hiss really, sometimes mine does it when exploring, and shows no signs whatsoever of aggression or defensive posture, but a few times he has done it really loud and you can see him poised to strike if needs be. If that happens, leave him alone. Don't just throw your hand into the enclosure to get him out, let him know it is you and not food.
There is no need to bath a ball python, they will shed perfectly if your conditions are okay. Bathing them could just stress them out when they are already stressed from shedding.
There is a ton of information all over the internet, and on this particular site in regards to breeding, it isn't something to just jump into, it requires reading and a knowledge of it. Also you need to be prepared for the amount of eggs that can arrive, and if you can care for them when they get bigger if you cannot sell them.
Google is your friend.