If they're in after school activities and/or have a job, then it seem unlikely that they would get into trouble anyways. Pushing the time back will make these after school activities unfeasible for many, and limit opportunities.

If you can't leave them unsupervised in the mornings, surely they can't be left alone after school either. Net net, there's going to be some time they're unsupervised. May as well let them get some rest. Maybe the lack of sleep deprivation will even encourage better decision-making.

After school has after school activities. It also typically means they don't need to cook if the parents are home for dinner.

Dictating diet by limiting options doesn't sound like a great plan to me.

You know what else is a non-problem? The current start times.

Their voice at the state level is highly diluted by non-interested parties. Voting for school board members tends to be more focused and doesn't have as many people voting based on non-school issues like you would for a general representative.

if a 15 year old can't be unsupervised at home, then their parents have different problems besides letting them cook for themselves.