Rare times indeed when I largely agree with Picard.  Although I will elaborate beyond him on a solution.

School hours of 9-3 are an archaic relic of the past, when moms stayed at home and kids worked the farmers' fields.  It creates a whole childcare crisis.  Most parents work 9-5, plus commute time.  In multi-child homes, losing an income is often cheaper than paying childcare.  There isn't enough time to cram in the curriculum, so PE gets cut, and schools rely on parents to help kids with homework.

The solution is to make school hours 8:30-5:30, with a designated hour of PE and a designated hour for kids to complete assignments - with the teacher there to answer questions - and longer recess and lunch breaks.

The biggest opponent of this is the teachers' unions.  They love their cushy 6 hour days while getting paid for 8.5 hours, on a 10 month year with 3 months vacation time.

It has been shown in Asian countries and some US charter schools this improves outcomes.