Quote 7
"Johnny! I nearly screamed. "What are we gonna do? They put you in the electric chair for killing people!" (4.32)
Pony's starting to see a long chain of violent acts stretching out before him. This fear of more violence is a big part of why he and Johnny run.
Quote 8
"You're the guy that killed Bob Sheldon. […] And he was a friend of ours. We don't like nobody killing our friends, especially greasers." (12.4)
Pony responds to this threat by breaking a bottle and then threatening the Socs with it. At this point in the story, he's in bad shape and hasn't been able to process any of the recent events. He seems to be changing, looking more to violence as a way to ward off the violence of the Socs.
Quote 9
"If you can picture a little dark puppy that had been kicked too many times and is lost in a crowd of strangers, you'll have Johnny." (1.49)
Ponyboy describes Johnny as totally isolated, like a lost puppy. The puppy in the crowd comparison shows that even though Johnny is surrounded by people, he's still isolated and alone.