All they have to do change the school hours.
Someone's going to get screwed, no matter what they do. When I was in high school, we had a somewhat late schedule, that was 9:30-4. I think I had to be at the bus stop by 8:30, and was usually home around 5. Around here, the earliest sunset is around 4:45 pm, which is from around late November to roughly December 13. The latest sunrise is around 7:27, and that's around the first 9-10 days of January. Although interestingly, since they started DST on the second Sunday of March rather than the last, depending on how early it falls, it puts it back to close to that. For instance, today's sunrise in my old zip was 7:24 (I'm just enough east now that sunrise is usually listed at 1-2 minutes earlier here). So yesterday it would've been around 7:25-7:26.
But, in the spring time, the days at least get longer, faster, and it seems like pre-dawn comes on earlier and lasts a bit longer, so even the time before sunrise seems a bit brighter.
But, during the shortest times of the year, there simply isn't enough daylight, to stagger school hours. Someone, somewhere in the time zone, is probably waiting for the bus in the dark, or getting dropped off in the dark. And that's probably going to hold true, whether you keep DST or not through the winter.
School times get staggered anyway, to accommodate school bus schedules. If all schools started and ended at the same time, we would need a LOT more buses and drivers. One thing I also remember about my old high school...it was the first in the county to have central air, so it had very few windows that opened. The idea behind it was that they wouldn't have to send the kids home when it got too hot. But in reality, whenever it got too hot, they'd send us home early, just like all the kids at other schools, so we wouldn't screw up the bus schedules. But then, when the HVAC failed, we'd get the extra "bonus" of a day off, or getting sent home early, even though that DID screw with the bus schedules.