I may be wrong, but I didn’t get the impression that the clock striking was for 8 o’clock. I was assuming that school started around 8, and Emma was talking to Henry before the school bell. Not being from Maine I’m not sure what time is sunrise, but the look of the town looked like it was just around sunrise to me.
Was gonna ask about the sunrise time, but hadn’t even considered that school would have started at 8. I’m thinking the clock was striking 7 and it reminded them they were working to a deadline so they’d better get moving.