Why did God allow Satan to have his time on earth? Why wasn’t it over when Jesus came back from the dead?

Why did God allow Satan to have his time on earth? Why wasn’t it over when Jesus came back from the dead? How can God be omnipresent and be unable to be in the presence of sin? Isn’t that impossible? Also, how can He associate with Satan if he cannot be around sin (like in the book of Job)?
There is probably no way we can know or understand why God has allowed Satan the impact on earth he has made. But, as the book of Job reminds us, Can you fathom the mysteries of God? Can you probe the limits of the Almighty? They are higher than the heavens—what can you do? They are deeper than the depths of the grave—what can you know? Their measure is longer than the earth and wider than the sea—Job 11:7-9. All we can know is that, as the Bible says many times, God is in charge; as He said through the prophet Isaiah, By myself I have sworn, my mouth has uttered in all integrity a word that will not be revoked: Before me every knee will bow; by me every tongue will swear. . . . I make known the end from the beginning, from ancient times, what is still to come. I say: ‘My purpose will stand, and I will do all that I please’—God speaking, Isaiah 45:23, 46:10. As God is the ultimate power in the universe, Satan only continues because, in some way, his presence advances God’s plans. We can never forget that Satan is the created one, God is the creator, and Satan is always under His rule. The famous example is Satan presenting Himself before God in the book of Job. For all that Satan accused God (and Job) of, he couldn’t do anything to impact Job’s life without God’s express permission and guidelines: One day the angels came to present themselves before the Lord, and Satan also came with them. The Lord said to Satan, “Where have you come from?” Satan answered the Lord, “From roaming through the earth and going back and forth in it.” Then the Lord said to Satan, “Have you considered my servant Job? There is no one on earth like him; he is blameless and upright, a man who fears God and shuns evil.” “Does Job fear God for nothing?” Satan replied. “Have you not put a hedge around him and his household and everything he has? You have blessed the work of his hands, so that his flocks and herds are spread throughout the land. But now stretch out your hand and strike everything he has, and he will surely curse you to your face.” The Lord said to Satan, “Very well, then, everything he has is in your hands, but on the man himself do not lay a finger.” Then Satan went out from the presence of the Lord—Job 1:6-12. This was later followed by another meeting between God and Satan: On another day the angels came to present themselves before the Lord, and Satan also came with them to present himself before him. And the Lord said to Satan, “Where have you come from?” Satan answered the Lord, “From roaming through the earth and going back and forth in it.” Then the Lord said to Satan, “Have you considered my servant Job? There is no one on earth like him; he is blameless and upright, a man who fears God and shuns evil. And he still maintains his integrity, though you incited me against him to ruin him without any reason.” “Skin for skin!” Satan replied. “A man will give all he has for his own life. But stretch out your hand and strike his flesh and bones, and he will surely curse you to your face.” The Lord said to Satan, “Very well, then, he is in your hands; but you must spare his life.” So Satan went out from the presence of the Lord and afflicted Job with painful sores from the soles of his feet to the top of his head—Job 2:1-7. In both instances, Satan was totally beholden to God; he simply could not go beyond where God had indicated. And, of course, one plan that God has that may explain Satan’s ongoing presence is for the continuing claiming of salvation of those presently outside the kingdom of heaven. As Peter said, The Lord is not slow in keeping his promise, as some understand slowness. Instead he is patient with you, not wanting anyone to perish, but everyone to come to repentance—II Peter 3:9. As the Bible makes clear in many, many passages, God has won, Satan has lost, and God will rule in heaven with all vestiges of Satan’s impacts and influences gone forever. As for Satan, he will be spending that forever in the eternal torment of the lake of fire. That is locked in place and, in God’s perfect fullness of time, it will happen. As God Himself assured the prophet Habakkuk, For the revelation awaits an appointed time; it speaks of the end and will not prove false. Though it linger, wait for it; it will certainly come and will not delay—God speaking, Habakkuk 2:3.
Regarding God’s omnipresence, there are some verses that seem to suggest that God’s presence cannot exist in the presence of evil. King David said, You are not a God who takes pleasure in evil; with you the wicked cannot dwell—Psalm 5:4. And the prophet Habakkuk noted, Your eyes are too pure to look on evil; you cannot tolerate wrong—Habakkuk 1:13a. Yet God in His omnipresence certainly does exist with evil; look at our planet. Most specifically, however, what the Bible teaches is that the wicked—those committed to a life apart from God through Jesus Christ—will have no hope of dwelling with Him. And certainly the coming presence of hell reminds us that, truly, God does not tolerate wrong. And, in eternity, God will not have any presence in hell; that place of eternal punishment will exist totally outside of God’s presence—certainly part of what will make hell “hell.” While God will always be omnipresent, He will remove that presence from hell, and from all who will reside there.
We don’t know specifically how God and Satan communicated in the “Job” story—just that they did. God never contradicts Himself—either in word or in action. He remained fully God, fully pure and fully perfect—even when in contact with Satan. Satan cannot touch God.