When the current balance is "0", it means that your credit card limit is not overdrawn. When the available balance is "9000", it means that this card still has this limit for overdraft or consumption.

Case: Suppose your credit line is "9000" and you overdraw 1000, then your current balance is "-8000" and your available balance is "8000".

Different banks have different expressions for the specific credit card limit. If you have any questions about your current credit card balance, you can call the bank's credit card customer service phone for consultation, and the relevant staff will tell you the specific use of credit card balance.