I agree with the other responders that family life becomes more demanding when the kids are in elementary school into early middle school. After that, the kids ghost you if they can. (Given that, I'd max that time when they can stand my company because when they decide it's not cool to have mom around, it will be very sudden - but that's just me.)

You will still need to outsource the care for the youngest child and need someone to watch the kids until you get home.
In the best case scenario, the kids are self-disciplined, a breeze to raise. In the worst case scenario, you need to be on deck for one or more kids constantly and that would erode your ability to focus at work. It all really depends on the kids and family life.

But 9-5 is a pretty good deal. I would give it a go and see how things work out.

The US is work-obsessed. What do you expect to hear?

You could quit again AT ANY POINT. I see no reason not to try and see how this job goes.

Try it for a year. As they get older and have a million activities it may get harder. Look for hours that can happen during the school day.