If it is K-1, it is worth trying! BTW, our son learned along with my husband (who had only played once or twice) and quickly surpassed him. I believe Chess for Children by Murray Chandler is the book that DS read that really helped him progress.

At the larger tournament we attended, there were clearly some hyper parents, and one or two obnoxious kids, but generally speaking, it was a pretty quiet (due to the chess games in progress), subdued environment. I would take along things for your son to do that are quiet, in the event his games finish before the time limit.