I really don't get why we agonize over "canon" or "non-canon", anyway. It seems to me that people who want to accept the Kelvin and its registry number will, and those who refuse to accept it won't. People waving their fists in the air and saying "It's in the movie so it's canon" are wasting their breath because those who don't accept it just won't, no matter who tells them to. Hell, Gene Roddenberry could come back from the dead this minute, post to these boards and say, "I officially endorse the U.S.S. Kelvin and its registry number with the zero in front of it" and someone will still grumble and moan, "But, Mr. Roddenberry!!!!!"
I really believe that people who absolutely refuse to accept this movie as established Trek canon (and I'm sorry to say that I know a few of them) should just call a "Highlander 2" on it; in other words, pretend it doesn't exist. Go see it at least (to show your support for the franchise), but when you walk out, just laugh to yourself in amusement, say" Oh, J.J., you fiend! Nice try, but no sale", and be on your way.