From this question I can assume that you misunderstood the whole concept of astral protection.
Astral projection is just another state of lucid dreaming. The whole out of body experience happens when you are in a semi lucid state, ie, during sleep paralysis. Your soul is not actually leaving your body, whatever you see during Astral projection is just the stimulation of your surroundings from your memory by your brain. It all happens in your head. People mix pseudoscience and magic with Astral projection but in reality it is just a dream state. For example try to alter a real life thing when you are in your Astral form. You might not see the alteration you made when you are awake.
So answering your question, yes you can time travel back to 2008 and enter your body and do whatever you like. But but it won’t impact the real life. Like I said before, it all happens in your head, it’d be just another dream.
This answer originally appeared on this Quora question on Astral Projection.