As per the recent tweet of CNBC TV 18, the Sources says that the GST Council has decided to extend the deadline for filing of GSTR-9 & GSTR-9C for FY18-19 till June 30, 2020. Further, the Filing to be mandatory for taxpayers over Rs. 5cr of Annual Turnover.
Source: https://twitter.com/CNBCTV18Live/status/1238794496885714944