I have doubts that they let him hold the scroll...
Luke 2:51-52 - Then he went down to Nazareth with them and was obedient to them. But his mother treasured all these things in her heart. And Jesus grew in wisdom and stature, and in favor with God and man. (full text here)
As observant and devout Jews, every year Jesus' family traveled to Jerusalem for the Passover Feast. This most important feast in the Jewish calendar served as a reminder of God's provision for his people during the plagues of and deliverance from Egypt. The observance must have held special meaning for Jews in Palestine as they suffered again under foreign rule.
Each year Jesus would have seen the spotless lambs being led to sacrifice, listened to the words of the Torah, and tasted the bitter herbs and other food symbolizing the Exodus story. At 12 years old, Jesus was on the cusp of manhood in his culture, straddling the line between childhood and manhood.
This is the only non apocryphal story we have of Jesus between his childhood and the beginning of his ministry, the only real insight we have into his character as a youth. The gospel writers had the intention of focusing on the ministry of Jesus rather than writing a biography. Apocryphal stories of Jesus have him doing supernatural things such as bringing clay birds to life, speaking in an authoritative manner that would have been considered out of place for one his age, or striking dead other children who upset him. In this story we see the true character of Jesus, wise beyond his years yet meek and obedient.
After the festival, his parents would have traveled back to Nazareth with many others heading that way. Mary would have traveled with the women, and Joseph would have traveled with the men. Jesus had apparently always been so obedient that it did not even cross their minds that he would not be with the group. Not until they settled down for the night did they realize he was missing. After a three day search (which likely included their travel time) they find Jesus in the Temple.
Jesus was sitting among the teachers, listening to them, and asking them questions. (This reminds me of when two decades later he confronts the religious leaders by asking them questions that reveal their erroneous thinking.) His zeal for learning the things of God was evident to all. Everyone who heard him was amazed at his understanding and answers, but later this same understanding will play a factor in his persecution and crucifixion.
Mary was understandably upset after three days of worry. Jesus' response to her reveals that on the brink of manhood and initiation into the Jewish community, he knew who his true Father is and what this meana for his life. Jesus recognizes that his sonship to the Father will take precedence over any ties with family or friend. He will follow God's will, even if it results in misunderstanding and pain for those he loves.
But after revealing these truths and foreshadowing his future, Jesus returned home with his parents and was obedient to them. He never responded, "Seriously? You want me to take out the trash? Don't you think the Son of God has better things to do with his time??" Throughout his life we see Jesus letting go of his divine rights, modeling how to live perfectly as a human, and saying yes to His Father’s plan.
That Jesus grew in stature and favor may make sense, but if he was fully God then how did he grow in wisdom? Isn't God omniscient? I believe that Jesus had to learn things just as all humans do, but he did it perfectly. In the incarnation, Jesus emptied himself of many benefits of his divine nature. As Philippians 2:6-7 says, "Though he was in the form of God, he did not count equality with God a thing to be grasped but emptied himself, taking the form of a servant." Somehow he was able to have the components of the divine personality (e.g. perfect faith, hope, and love) while giving up things such as omniscience and power. We see this later in his ministry through statements such as Matthew 24:36 when he says not even the Son of Man knows the time of the second coming and through the many times in his ministry when he needed time of rest and prayer to "recharge" after long sessions of healing and preaching.
May we have the same zeal as Jesus to understand the things of God. May we desire to submit to authorities and the will of God rather than seeking our own comfort and praise. May we be willing to be about our Father's business regardless of the cost to us or those we love.
It was his Father's business made him sweat great drops of blood; his Father's business ploughed his back with many gory furrows; his Father's business pricked his temple with the thorn crown; his Father's business made him mocked and spit upon; his Father's business made him go about bearing his cross; his Father's business made him despise the shame when, naked, he hung upon the tree; his Father's business made him yield himself to death, though he needed not to die if so he had not pleased; his Father's business made him tread the gloomy shades of Gehenna, and descend into the abodes of death; his Father's business made him preach to the spirits in prison; and his Father's business took him up to heaven, where he sitteth on the right hand of God, doing his Father's business still! His Father's business makes him plead day and night for Sion; the same business shall make him come as the Judge of quick and dead, to divide the sheep from the goats; the same business shall make him gather together in one, all people who dwell on the face of the earth! Oh, glory to thee, Jesus; thou hast done it! Thou hast done thy Father's business well. -Spurgeon