This is one of those incoherrent parts of the whole GOD scenario.
If there really were an all-powerful God that spirtis could know for zillions of years how could he even dare to think he could pull off a rebellion. He would have to really be stupid- an idiot. It is even more implausible that he would be able to persuade a substantial number of other spirits to join him. And why would they in turn follow and cooperate with the Devil? Wouldn't they pretty much have their own evil agenda?
If there IS a Devil than there cannot be an all-powerful God.
But - allowing the scenario given in the Bible - If Satan repented - he would cease to exist. He would no longer be Satan.