Kids trained to 'push' virtual soldiers on a digital (AR/VR) tabletop. The soldiers turn out to be real people. There are two kids (boy and girl?) who are able to sneak out and talk to each other during their training. I think this was a YA novel as I read it in elementary school in the late 90's/early 00's
Found it! It’s called Virtural War. After revisiting it, I don’t recommend reading it.