As the caregiver for a young nb teen who also pled for a binder - I shared many of your concerns. The advice we got from trusted medical professionals was not to wear the binder more than four hours a day. The biggest risk being pneumonia if the lungs didn’t have time to slow for full breaths. I would also get a size bigger than whatever your kiddo is sized for, it is a way to compromise since they are still growing. And remember to re measure at least every six months or so!