You really have my sympathy. I've been there. I know that some don't find an hour change to be that big of a deal, but I've always put too much effort in finding flights that would be the least disruptive to the kids' schedule (and my kids have a decade on yours!) It has been no small feat since CVG was gutted. We've even decided against some trips when we found nothing but a whole lot of ugly when shopping potential flights.
There is another a nonstop leaving from CVG @ 4:00pm. Don't know at what fare class you booked, but the CVG and CMH fare are within a few bucks right now. The right CSR might be able to make that work for you.
Either way, you've got me thinking about how nice it would be to escape Ohio for some LA sun when December rolls around.
Good luck!