Tbf, Blizzard doesnt need to say a patch is delayed when they've given no release area for a patch.. the "schedule" we as a community and that they've been having internally has never been formally confirmed by blizzard, and we cant use the numbers for that reason alone..
If they had said "Patch 9.1 will be out on x date in March" they would've needed to delay it, yes.. But they've never given an estimate on the release of the patch, and therefor has NO need of delaying it..