Put down the dish with what the dog should eat, and give it 15 minutes to eat. Then take it up. Do not give it anything to eat until its next scheduled meal. In a few days, it should be eating what it needs. Continue to check its ribs and adjust the food as needed. This is not easy. I had a Shepherd go 3 days on a few nibbles. I was a wreck, but she was fine. It is almost unknown for a healthy dog not to eat what it needs. Unfortunately, in too many cases, it is less than the package says, and less than the owner thinks the dog should have. Many dogs are quite good at holding out for tastier chow. Like kids, sometimes it calls for tough love.
Over feeding can add to the problem. See
http://www.puppychow.com/products/po...condition.aspx
And please, when you literally get back on your feet, get them to the vet and have them spay/neutered. Expect a great challenge out of them to get together and produce an unwanted litter. Nine months is much too young to be mated.