what insight came to scout as she stood on boo radlwts porch after taking him home

She sees that Boo is essentially a "mockingbird" and a human being. She says the simple words "Hey Boo", like she has known him all along; in a sense, she has.

Standing on Boo's porch, Scout look out over the neighborhood imagining how Boo must have seen it, and how, for all these years, he watched over "his" children. Back home, Scout sits with Atticus, who begins to read her one of the scary children's stories he has picked up, which ironically mirrors the story of Boo Radley. Scout says she wasn't scared by the night's events, saying just as Jem had on their fateful walk home, that "nothing's really scary 'cept in books." She falls asleep while Atticus reads to her, and wakes up while he carries her to bed. She tells him she was listening all the time, and that the book is about a character who was chased and caught and then found to be innocent and "real nice." Atticus tells her, "most people are, when you finally see them." Atticus then spends the rest of the night by Jem's side.