Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
It may take a little more time to appear, esp. if your credit card payment is not rapidly and easily done by whoever is at the other end... or perhaps, they don't work 24-hours-a-day??
If the payment's value does not appear in your account by and by, then you need to inquire both with DoubleDown Casino, and with your bank (in case it needs to be canceled.)
I wouldn't give up on it until at least 10 a.m. tomorrow (the 10th March.)