Are you sure you were on 9a? That wasn't even announced until December 2011:
http://www.openreach.co.uk/orpg/home...es/nga03311.do
It doesn't specifically date 9b anywhere, we just know from how the numbering works that it'll mostly come after 9a. Even BT themselves don't have fixed dates.
(The big spreadsheet says RG41 was mostly phase 4a)