GELD HIM NOW!!! If he is already acting super playful and suddish he will only get worse as he gets older. He will be very difficult for you to break and agressive. If you must keep him a stud, there is really no way you are going to beable to control him behavor. I would keep a halter on him at all times with a 12inch lead hope attached, so you have a better chance of catching him.

I am guessing this is the same horse you are referring to reguarding the bit issue. No hackamore for him, you will have no control.