To be honest, there really is no such thing as a "tame" snake. The most you can expect from a reptile is tolerance towards you. Any animal with a mouth is capable of biting especially if it is startled, cornered, scared, hurt, hungry, or feeling defensive. A snake that is unable to flee a situation it feels is threatening has only its teeth left as a defense.
As Aaron stated already, give the little one some time to acclimate to his new surroundings, leave him alone for a week or so, make sure he has plenty of hides (2+) to allow him a sense of security, be patient, and above all, remember, this BP is only 3 months old, if you do get tagged, it's nothing.
Personal Experience: My general rule of thumb with newly purchased BP's differs a bit only because of the ones I have kept. I won't handle my newly obtained young BP unless it has eaten for me reliably 3 times. So 3 weeks of extremely minimal handling. But that's just from some of my personal experiences with more nervous young balls...To me, it's more important that the snake is healthy and feeding as opposed to its handling tolerance.
Good luck