If we look at Chapter Twelve, which is when Maniac Magee finds his first more stable "home" compared to the shed in the park, we can see that Manic Magee defines home as being an address that is recognised in the eyes of the world. Note the way that he is unable to go to sleep in the Beale's house until he has performed one very important operation:
Before maniac could go to sleep, however, there was somethign he had to do. He flipped off the covers and went downstairs. Before the puzzled faces of Mr. and Mrs. Beale, he opened th front door and looked at the three cast-iron digits nailed to the door frame: seven two eight. He kept staring at them, smiling. Then he closed the door, said a cheerful "Goodnight," and went back to bed.
Maniac Magee finally had an address.
For a boy so used to instability and having moved around so much, we can see the importance of an address and the way that it symbolises a fixed abode and stands in opposition to his itinerant lifestyle. However, if we look at the final chapter, when Maniac Magee is sleeping, in all places, in a buffalo enclosure, when Amanda drags Maniac Magee back to his home, we can see that home to him means something much more important. It is somewhere where he belongs and is loved and is accepted without question.