It has been confirmed to me by Microsoft staff member Anthony as of 11:45 est. That the game will in fact not be out until tomorrow (Aug 22) to my and many others dismay. I took off work for this day lol. I will post the convo below, according to Anthony the release date for XBOX users was always Aug 22, and for those saying its XBLA's policy or procedure to release games on wednesdays that was not confirmed at all by Anthony, but then again he didnt say it wasnt either. So i guess the debate continues...
Anthony: Thank you for contacting Xbox Customer Support my name is Anthony. How may we help you today?
James: Hi, i was just wondering about Counter Strike Global Offensive. I purchased MS points to purchase it for today because AUG 21 is the release date for all platforms but its not available for purchase on XBLA
Anthony: It is actually available on Aug. 22, 2012.
Anthony: So tomorrow it will be there.
James: =( lol
James: darn i took off work on the wrong day
Anthony: So by tomorrow everyone will enjoy it.
Anthony: Im waiting for it as well : )
James: did it get delayed to tomorrow or was that always the original release date for xbox?
James: is that just a XBLA thing for games to come on wednesdays?
James: cool beans =) maybe ill cya in-game
Anthony: It was the original date.
Anthony: See you in game too.
James: oh ok then wikipedia has lied and misled me again!
Anthony: Well wikipedia is not that accurate always.
James: lol ok thank you sir, cya in game tomorrow!
Anthony: Thank you as well.
Anthony: Have a nice day and take care :)
Anthony: Thanks for contacting Xbox Customer Support and have a great day!