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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.