I don't believe he can do this even on a newer site like this with over two months to wait.
i dont think that it is a very new site as i found an official thread of this site here:
https://bitcointalk.org/index.php?topic=645747.0 the thread was started on june 09, 2014 so you can say that it is a 2 years old site but i have to say that it is not much popular though.
Normally you can not cancel bets once they arr placed on casinos. If that were the case then alot of people would be doing this for their bets too.
yes you are right but since it is a sports bet and the game is not yet started, there is a possiblity that the bet could be cancelled if op contacts the support.