Just read this thread, but was clear that it is corn ear worm when you first described those almost perfectly round holes. Corn iear worm is so destructive because they go from one tomato to the next and will destroy a hole cluster while eating very little. They are very difficult to control. Don't plant your corn too close to the tomatoes. When I find a tomato with a corn ear worm hole, I generally toss the tomato far from the patch after killing the worm if present. I also carefully inspect any other tomatoes in that cluster and in any clusters that are near. Good luck. You are dealing with one of my least favorite pests.