Okay, if by 9, friend means people you've got:
Kenji
Otcho
Keroyon
Mon-Chan
Yotshitsune
Marou
and Donkey.
Now, Donkey being dead, we can replace him with Yukiji, who also knew about the symbol, right?
And there is also Fukubei, the guy at the reunion, and Sadakiyo, the mask kid.
So that's 9 people.
Now, if friend is Sadakiyo, would he include himself in this? I don't think so. It means 9 adversaries for friend to fight.
So, yeah, I don't think that Sadakiyo is friend. For now at least.