I can't really speak about the medications but I understand about the impulsivity and inability to keep hands off of stuff. My difficult child is the same way. Not as bad as he was in some ways but also has gotten more sneaky in others. We adopted him at the age of 10 (he came to us at age 9) and he's had that issue since long before we got him.
Since yours is so young, you may want to try techniques like someone else mentioned (fold your arms! or hands behind your back/in pockets....something like that). Obviously, it won't help overnight, but it could be something in the long run that would at least make pause a bit. With us, we basically have to literally lock everything up we don't want messed with, taken, broken, taken apart, thrown away, given away......you get the idea. I even have to keep all of my bathroom stuff (make-up, shampoo, hair products, everything) in my room, locked up. difficult child has used a full bottle of my conditioner to wash his feet, has "played" in my hair gel/pomade stuff, cut the cords off of my curling irons to make stuff...you name it, he's done just about all of it.
That may be your main "preventative" action at this point until you can find something to help otherwise. Sorry I couldn't be of more help. Good luck and sending hugs.