You would get wealth debit card when your account varient is converted to wealth. IDFC would generally convert your account to wealth if your TRV is more than 10 lacs with the bank.
I recently got my account upgraded to wealth like 10 days ago, however if you have wealth credit card then why do you need debit card? I would always prefer to get credit card over debit anytime.. unless is there some benefit in debit wealth which is not available in credit wealth?