As per information on GSTN website GSTR-9 of FY 2019-20 is available now for filing.
Facility to file annual return in Form GSTR-9 for FY 2019-20 is now available. The Form is enabled for taxpayers whose table 8A computation has been completed. Computation of the table 8A of the said return for auto population from returns is under progress which is likely to be completed soon. Please ensure that all applicable returns of the said year have been filed before attempting to file the said return.
It is also explained by GSTN that If the tile for filing the same is not enabled, wait for some time as computation of table 8A might be under process in your case which will be completed within 2-3 days.