I have 3 teens and I painfully recall my now 18 year old son wanted me to be the Activities Director constantly. My other two were fine to play on their own. Same with my groups of dcks some are totally fine occupying themselves, and others wander around in circles....
I had trouble with toys being thrown and ending up on someone's head (usually mine)...it hurt a lot, so I introduced 'Toss Time'. I have a bin filled with soft toys; pool toys are great - the kind that are soft and spongy, nerf balls, stuffies. I tell the kids they can only throw at 'Toss Time' and then we all go wild and crazy without hurting anyone... to clean up all the toys they have to try and throw them back into the bin. I introduced it to my younger group too - 15 months, and seems to work. If a child does throw a toy, I tell them immediately no, and that we only throw soft toys at Toss Time. It's worked for me for a while now.