The backlog can be more than 9 months. I know.
I took the GAP Closing courses In June 2016 and submitted them promptly, but did not get the stickers until March 2017.
My license consultant is in frequent contact with NMC and my evaluator about various applications. He says NMC is very very understaffed, and he's never seen it so bad before.
Simple applications (such as a recent academy grad upgrading from 3rd Mate to 2nd Mate with one seatime letter with over 365 days from one vessel over 1600GRT) may not take nine months, but I hear about them taking four months.
If an application is for an unlimited license with a tonnage restriction, or includes combined tug & barge tonnage seatime, it will take a very very long time.
The problems at NMC run a lot deeper than last minute Gap Closing courses. That's just a convenient excuse to cover up gross incompetence and neglect from the top down.