My guess is, if you press 9, you'll be in a world of trouble as there a multitude of scams that revolve around the call receiver pressing 9...all of a sudden, you could end up with a $3,000 bill from someone in prison who gained access to your number and, because you pressed 9, it allowed them to abuse your phone service without you even knowing. Not 100% sure but why risk it. If you want to lower your credit card interest rate, contact your card company directly.