I'm taking this into Possible Game Breaking measures. I need a list of Glitches in certain games such as B2/W2 or X/Y. This is for finding Victini. I need every possible glitch. I'm never going to use a Cheating Device.
According to these lists of Generation 5 and Generation 6 glitches, no. You cannot obtain Victini legitimately without its event by using glitches, using PokeGen, or testing your luck on the GTS, where you can't even obtain event legendary Pokemon.
Source: Above Links