Gstr-9 Annual return

please guide on following points:

1 I had not paid rcm from july to oct 2017, but i want to declare such liabilities in Gstr 9 in table no 4. such amt is to be paid as additional liabilities through DRC-03,

can i claim the itc of such rcm in 2019-20.

Is it mandatory to disclose and paid such liablities .


2 Whether interest is to be paid on such rcm liablities not paid , even if i was eligible to avail such itc on rcm in next month 3b