Hi Alora,
My Teddy is slightly smaller than Henri. You wrote to me that Henri is 9 pounds with a 14" girth. Teddy is 8 pounds, 12 ounces with a 14" girth. He wears the Size 3.5 on the middle hole. The 3.5 is the correct size for Henri.
Here is Teddy on the right with the Size 3.5:
When you put the harness on Henri, is the buckle to his left paw? The harness is supposed to fit directly against the body without cinching the skin.
If you could video tape what Henri is doing, maybe I can help you figure out what is wrong.
Thank you,
Kristin
Here are more pictures to help with how to put on the BB: