"Outcasts"

I think that chapters 8 and 9 were very important.  They helped to better explain Chris and emphasize the fact that he's not like all the other crazies.  When writing, Krakauer found so many people to interview about Chris because he was so memorable.  There was just something about him that made it impossible for his peers to forget.
I believe names are collections of sounds that please our parents' ears.  The sounds are associated with experiences.  The experiences and what we use to put meanings to the names.  And from there, our parents decide on names that they hope their child will one day embody.  But what's more important, is who you, yourself, want to be.  Christopher McCandless changed his name to Alex Supertramp not only to avoid being found, but because he felt it better expressed him.
I figured I'd look up the names.  Christopher actually means 'Christ-bearer' and Alexander means 'defender of the people', so I can see the appeal there.  Plus Supertramp reminds me of the beginning of the novel when rubber tramps and leather tramps were being explained to Alex.  He probably chose Supertramp because he walked, drove, canoed, trudged, and whatever else he had to do to get where he was going.