I think that one of the best examples to unify the prompt with the text would have to be Amir. The opening of the novel is one in which there is a stated desire to "be good again." The experiences of Amir's childhood influence this need to be "good again" and help to formulate why Amir does what he does as an adult. His experiences of discarding Hassan largely determine the adult that Amir would become. His standing silently while Hassan endures the worst of abuses, and secretly plotting against one who served him so loyally were childhood experiences that played a large role in establishing the adult he is to become.
It is from his childhood experiences, actions that denied a sense of "good" within Amir that fuel his desire to return to Afghanistan, make good on a friendship promise to Hassan, and rescue Sohrab while facing down Assef in the process. For Amir, the experiences of childhood determine the adult he becomes. His journey towards redemption involves him going back to his past and his childhood and making right that which is wrong. In writing about the importance of childhood experiences in determining the arc of one's adulthood, Amir becomes an embodiment of this evolution and pattern of progression.