How much is taxable if I lend money from my credit card within an interest-free period?

Taxable mentioned here is Let us say if I lend 3 lakhs for 3% for 30 days within interest free period of credit card through online transfer not by withdrawing cash, the borrower will return 3lakhs and 9000 interest to my savings account. So my doubt here is total 309000 taxable or 9000 alone taxable, since 300000 comes to my savings account to settle my credit card bill will 300000 also considered as income to me. Kindly help me on this