Credit card balance transfer

So I have about $9,000 on a credit card with a 29.9% interest! Yes I know, insane! I was looking to transferring this to a credit union credit card with no interest for 12 months. I have an amazing credit score and I want this card paid off ASAP. Is this a good idea or no? Also, I had this credit for almost 10 years(haven't had that balance on there that long, medical bills is the cause of it). I have a very high limit (clearly I won't even use the card again lol) but will the card automatically close? Thanks!!