ITC restriction applicability

What are these links ?

"Save as otherwise provided in these rules, they shall come into force on the date of their publication in the Official Gazette."

This means the rules are applicable from 9th October, 2019. According to me this should not be applicable to GSTR 3B of September month, since we could've filed the same before 9th October as well. For the purpose of uniformity we can presume and interpret that these amendments are applicable from 9th October onwards. i.e. we need to comply with the rules for returns pertaining to the tax period commencing from 9tn October onwards..

Seems to be right justifications.
Thanks