Two things:
First, do you think its possible that this pup isn't 9 weeks old but younger and is traumatized to leave the litter? She still should be eating, but my point is, when they're that young they really need a lot of cuddling and warm snuggling. Bo came to me at 6 weeks, was a happy little guy, but loved to snuggle! I would wrap him in a Turbi-twist and he'd lay snug and warm for long stretches perfectly content. They will sleep curled up in a ball the first weeks. This seems like a pup that you're going to have to devote some quality time to.
Second, if your vet is not familiar with the needs of toy dogs,
SWITCH VETS!! I've seen too many posts on here of loving owners who have watched their babies crash with hypoglycemia. Good luck, your baby will be in our prayers. Bo sends puppy kisses!!
