We have a tradition of taking a picture in the front yard every first day of school. A friend of ours takes one in the exact same spot every year, just like her parents did when she was a girl. It is really neat looking through the photo album from when the mother was a girl. Since she's always standing next to the same front gate you can see the changes in height and in her face from year to year from Kindergarten through 12th grade. Family rituals like that are a nice way to mark certain times as special, and to mark time as we move through life. Like our unique ways of celebrating birthdays and holidays, they can be a nice source of connection and meaning. Anything regular like a family ritual also is helpful for those kids who tend to feel a bit more anxiety when starting school. The familiarity of the ritual can be grounding for them.
I like the practice, which I don't recall happening as a kid, of starting the first week midweek, so the transition is a bit less traumatic. Three days and you're through your first week. Good luck to everyone with the the first day. Here's to a new year with new opportunities.