The final lines do not suggest that the boy will be abused on the way home. Instead, he is hoping that someone who loves him will notice that he is missing, come and find him, and encourage him to come home. The fact that he wants someone to "whip him down the street, but gently, home," shows that he wants to be missed and fussed and worried over, and that -- when someone notices that he is missing and begins to worry about him -- this heightened emotion might translate into a bit of anger at him when he is found. However, this heightened emotion would only really be indicative of how nervous and upset that "someone dear" was when they realized that it was late and he was not at home. It would show how much that "dear" one cares about him.
I think, ultimately, his desire shows his wish to be wanted, to feel important. If we isolate the final words in the couplet -- "come" and "home" -- they can be strung together to form the imperative statement, "come home," and this meaning would likely register with readers as a caring statement. When someone tells us to "come home," it is usually because we are missed, that our presence is desired. Children are used to being told to "come home" at night by their parents, but it doesn't sound as if this boy is. The fact that he's alone, at night, out of his house, makes me think that his friends have all been called home. He has not been called home, and he wishes that he would be. Thus, the poem becomes further inflected by his deep longing, conveyed already by the content of the final couplet but enriched, certainly, by the words on which the poet finally lands.