To file GSTR-9 with Tally ERP 9:
1. Go to Gateway of Tally > Display > Statutory Reports > GST > Annual Return > GSTR–9.
2. Select the financial year and press Enter.
3. Fill in the details and make necessary corrections if any.
4. Click on the 'Export' button to export the data.
5. Go to the GST portal and log in using your credentials.
6. Click on 'Services' and select 'Returns' > 'Annual Return'.
7. Choose the financial year and click on 'Prepare Offline' > 'Download GSTR-9 Offline Tool'.
8. Open the downloaded tool, import the Tally data and click on 'Generate JSON File'.
9. Upload the JSON file on the GST portal and file your GSTR-9.
