8 months old...horrors! haha Oh, they really do learn early how to control us.
She simply does not want quiet time and has learned that barking will get her what she wants. I do agree that perhaps a Kong will keep her busy and quiet...but, I do think that perhaps you may have to be patient and listen to her for a night or so and not give in to the urge to stop it. Once she learns that you will not pick her up, I am fairly certain this will stop. Good luck! I do know how difficult it can be.