Trek works best if you look at it as examples from all the various universes. In Universe #1285 JTK has three nephews. In Universe #250 he only has one. In a similar fashion Universe #29042 we see a James Kirk with the middle initial of R. There are no continuity errors, just an infinite numer of universes, some quite similar, some remarkably different.
The run from TOS through ENT are fairly similar in their history. The 2009 movie is much more removed but still using the broad strokes.
It all fits.
Bashir: What I want to know is, out of all the stories you told me which ones were true and which ones weren't?
Garak: My dear doctor...they're all true.
Bashir: Even the continuity errors?
Garak: Especially the continuity errors.
I find that a very unsatisfying way to look at it, since it's basically saying episode X didn't happen to the same crew we saw in episode Y or novel Z. I prefer to see all the episodes, movies and books (excepting the ones deliberately out-of-continuity) as windows into some "real" (for lack of a much-needed better word) Trek universe. Some windows are clear, others are fogged up to varying degrees, jumbling the details a bit.