Filing of Annual Return ( GSTR-9 ) has been made "OPTIONAL" for Taxpayers whose Aggregate Turnover is upto Rs. 2 crore. Notification No. 47/2019 - CT, dated 09.10.2019 has been issued to give effect the above decision.
So if your Aggregate Turnover is upto Rs. 2 crore, then it is optional from your part to file Annual Return for FY 2017-18 and FY 2018-19.
And if you want to file Annual Return, then the due date to file FORM GSTR-9 for FY 2017-18 is " 30.11.2019. "