Since the events of the 2009 movie take place in an alternate timeline to that of the original series, there is no logical problem with it being canon. The hows and whys are detailed here: Bob Orci ...
Nero was captured by the Klingons and tortured for almost 25 years. My guess is it drove him insane, leaving nothing but revenge in his mind.
I noticed the hover bike in the scene where the police chases young Kirk. While the concept of hover bike itself is not new, I believe it is new to the Star Trek universe.
The Halo universe has Dyson Spheres. The setting of Halo:Wars was a Dyson Sphere.