Factual error: Right after Tweeder scores the first TD in the second half against Gilroy, it shows one of the Gilroy players on the bench take off his helmet while on the field and throw it down. This should be an unsportsmanlike conduct penalty as well as a too many men on the field penalty against them. (01:33:00)
Factual error: Right after Lance gets hurt and Mox replaces him Mox's first play is a 40 yard pass for a first down after which everyone starts yelling he needs to stop the clock and the camera shows the clock moving. The problem is that in high school football the clock stops on first downs while they reset the chains so the clock should have stopped running until the first down markers were moved and the ref set the ball.
Factual error: In the game against Gilroy, Gilroy would be penalized quite a few times for their bench being on the field.
Factual error: District Titles are mentioned numerous times, but when Coach Kilmer is leaving the locker room at halftime of the last game all of the banners say "Division Title" which is not an award in Texas HS football.
Factual error: In the final game for the district title, the opposing team would have had several penalties called on them for unsportsman like conduct for the breakdancing moves in the endzone, and all the other dancing the team did.
Answer: There's no rule in any sport, at least none that I could find, that requires a team to have, or listen to, a coach. Obviously in most cases it's a good idea, but if the coach were poor and/or working against the interests of the team, the players wouldn't be breaking any rules by simply ignoring them and listening to someone else.