I'm back to working with 8-10 year olds after working with older, advanced middle school distance runners for the last couple of years including 3 individual JO National medalists last year. This older group was ready for modified HS workouts but the younger kids will not respond very well to "training". In fact, none of the kids I coached as newcomers a couple of years ago are still around including one that scored two individual medals at JO Nationals.
What I'll be doing in the early part of the season is a combination of running and drills. Saturday's workout was 3 sets of - 600m easy on grass to the base of a hill, recover, one 10 second burst up the hill, jog back, a 10 minute set of drills, plyos or core work, repeat. The kids got a light aerobic workout, a small amount of form/strength work on the hill and learned some of drills that we do. In the past I might have had them doing easy, continuous mile loops around the park or sets of 200s but I don't think that's a sustainable approach given my experience of a few years ago.
They had fun at our first practice and they got to know each other for a change. You don't learn much about your teammates when you are lining up for intervals.
Another piece of advice is to limit the competition in practices. When we did the hill charges, for example, I sent them one at a time, spaced out so that they wouldn't overlap rather than all at once. In groups where every workout is a race you eventually lose strong runners that are losing out on stronger runners.