Shippou-Sensei
4:1:2.5
Shippou-Sensei bring your manga brain to bear on this problem
I hear and obey...
I think that if the kid likes the punchy fighty stuff then there is a glut of shounen stuff. The one problem might be tone. some of it can get a bit dark or violent. Fine for say 12+ but for 8/9 i think it may be a PG rating att least.
a bunch of this stuff is online so i'll post a link to some of the more popular ones
One Piece Manga - pirate themed stuff. main character has rubber based superpowers. very big on the idea of comrades (how do you translate nakama?)
Naruto Manga - ninjas, ninjas everywhere
Dragon Ball Manga - old school stuff
InuYasha Manga - well i kinda had to include this one because of my name.
Shoujo stuff is good too
Cardcaptor Sakura Manga - As tomoyo would say "sakura-chan suteki desu wa"