Attempts at plot holes: why didn't Vulcan's Debris travel back in time and create an alternate universe?
Because it was just debris, not a big ass ship with advanced weapons, and so the Kelvin (or whatever) just had to make a course correction to avoid the debris instead of getting annihilated.
Why after declaring weapons offline is the Kelvin still able to fire on the the enemy?
Because it was temporary and fixed by the next scene.
Why isn't Delta Vega pulled into the Vulcan Black Hole?
Because it is far away enough to not be affected. The Enterprise traveled away from imploding Vulcan and had still been traveling at impulse for a few minutes before coming to Delta Vega.