9 weeks old breastfeeding baby?

Small babies need to feed often, and they often make up for the sleeping time by eating more frequently when awake. She is moderating her own intake to match what her body needs. If you are pumping after a feeding, you will not get too much milk because your daughter is getting it. There shouldn't be a lot left. If you are looking to express more then you might wait an hour when she is sleeping and pump then. The best indicator of having enough milk is the baby - if she is having 8 wet diapers a day and gaining weight and developing well, then she is doing fine. Don't get hung up about the numbers when you are pumping.