Spock and Nero go back in time, Vulcan is destroyed, history is changed.
Does Voyager still send Braxton back in time, thus triggering the computer revolution as we know it?
Does the Enterprise E still come back in time to help with First Contact?
The divergence occurs in 2233, as per ST09. As of that instant, both the Prime and Kelvin timelines are possible futures. Therefore, anything that happens IN those futures will still happen. Including anyone travelling back in time FROM those futures.
Theoretically, travellers from both timelines could even meet each other, if they came back to any point in time prior to 2233.
And Data's head is still underneath San Francisco.
