People not fully legally responsible for themselves should not have any social media account, uncontrolled electronic communication devices or services, or Internet access.
At all.
These are for adults: they are the wild west of information sharing and communication. If children wouldn’t be allowed to go into a bar at midnight and go have an anonymous conversation with someone in the rest room stalls for any reason, why on earth does anyone think that the Internet is something they should have any access to without the strictest of controls and restrictions?