I added my cards on September 28, received a call from HDFC executive following day for verification and today they are shown as active instead of verification pending.
I was able to pay my bills from October 1 without any issues. Just keep in mind that your payment might take more than 3 days to reflect in your credit card.
Indusind : payment was real time just CRED.
CITI, ICICI and RBL : still I don't see anything.