> There's also the much-cited football problem: if high schools ended at a more reasonable hour like 3PM or 3:30PM, this causes problems for football coaches, who might see their after-school practices running to 6PM or something.

I checked my high school and others districts to confirm they operate on an 8 am - 3 pm schedule +/- 30 minutes. Is this uncommon?

Same over here in Aus, those are standard hours for most every school I've seen.

Little later in my experience (vic) 9am to 3:20

That's standard UK primary school (4-11yo) hours too.

And pretty much the same for secondary.

560 min or 650 min periods, 45 min lunch, 15 min morning break. 6 hour minimum day. Any extra time is padding for registration or longer breaks.

I don't think any of the sports coaches I played for would have cared if practice took until 6pm. Sometimes it did take that long (or longer, until dark) except that after the state-limited amount of practice time an "optional" senior-led workout was what we told everyone we were attending. If we had more time before school, our light conditioning could have been a full-blown practice.

It could just be daylights saving time fooling me, but I did lacrosse in high school and practices went until it was dark.

Here in Finland, schools start at 9 or 8 depending on schedule and end between 1 and 3 with enough time for Sport after. I think moving up school time would be feasible for US too. As an Exchange student during my HS years, waking up at 0515 was just insane.

Even later actually, since 75 minute classes are pretty common nowadays it's often 8:15,9:45,11:30 (lunch break causes the inconsistency here).

When I was in high school in the US 20 years ago, it was 8:00am to 3:15pm.

This seems pretty reasonable to me.