We gave our kids hand-me-down iPads starting at about 10, with parental controls, rules around not allowed in bedrooms, charge in living room, etc.
Started with imessaging family, then they could text aunts & uncles, then cousins.
Kids could join some social networks like Strava for running, GospelLiving (world's best but most unsuccessful communication platform ever), GroupMe (what our ward actually uses), etc.
Instagram with 15 minute/day parental controls built in to Apple's iPhone parental controls.
Everyone (parents included) charges their devices in the living room, away from all bedrooms. Mostly no devices after dinner.
We do have a dumb phone cell phone the kids can take if they need a phone but don't have their own.
My youngest is 13, seems to be working well.