The Wyrmhole's recommended RPG systems for younger heroes are:
More resources for the D&D After School Program are on the right.
The videos below are discussions between experts on how this hobby can be beneficial to the development of children, young and old.
Devices are strongly discouraged, if not outright banned, for kids sessions. Players are given paper sheets for their character, abilities, spells, map layouts, etc. which they fill in themselves, with assistance where necessary.
This section may contain spoilers!
Here are some resources that any Dungeon Master (young or old, aspiring or experienced) can use to get players rolling dice and thinking in dungeons.