Okay let me give you and
Golfing Gator an idea of what I mean. Elem schools start usually around 8:30, give or take. Right now, far west end of the EST, our latest sunrise is 8 Am. So yes, students are spending a limited number of weeks in the morning darkness.
Now back that sunrise up to 9 AM. It's not like the sunrises at 8 AM for a month, then at 9 AM for two weeks, then back to 8 or whatever. We spend a whole month--from late Dec to late Jan--hovering around that 8 AM sunrise time. By the end of Nov we are already up to a 7:45 sunrise.
If you convert that 8 Am month to 9 AM, that's a LOT of morning darkness, so a lot of time for accidents to happen. It's not just "kids do it now", it how long does that danger last. If we have a 9 AM sunrise in the coldest part of the year--another complication--a long darn time.