I helped coach but it was 6/7 year olds at the time. At that age misdirection was key for offense and like previously mentioned defense was stay in your zone (defense was the toughest because kids always had the tendency to follow whoever they lined up in front of instead of staying in their zone, then when the misdirection came back their way they had drifted of the zone following who they were lined up with). You can try man to man but if they have a matchup that doesnt go in your favor they will expose it and keeping going back to it. Hopefully at 9/10 the schemes will sink in with them and make it a little easier.