The year that I coached Destination Imagination (formerly Odyssey of the Mind in these parts) was our worst in terms of being over-scheduled.  I co-coached then DD9's team.  We met after school at my co-coach's house.  Although it was a friendly atmosphere for my 2 younger DCs, it was another day out of the house for them after school.  It turned out to be a huge negative for then DD7 who was struggling due to some 2e issues that we hadn't identified at that point.  
I guess I would caution that coaching DI is a huge commitment and to consider your other kids (if applicable).  Ideally, I would recommend recruiting your own team so you have an idea what kind of behavioral issues may be present and whether the group has the desire to work together.   I also would find out what level of support is offered by your school to the coaches.  I previously had coached at the K-2 level and did not find it to be as onerous as the 3-6 level.