9mo old fever of 2 days subsided, drinks all bottled and diluted juice throughout day, refuses solids, wet diapers considerably low still. Worry?

Hard to tell. There are several possibilities, sore throat , ear infection and more. I would go see your pediatrician.
Low? If there isn't a wet diaper within 6-8 hrs and if there is one with only a small amount of darker concentrated urine it's concerning. Particularly if your child is acting lethargic. It's reassuring that the fever has subsided. Other signs of dehydration include dry mouth, eyes that appear sunken, lack of tears when crying, cool skin or something we call delayed capillary refill.