What's the highest Intelligence check required at any point in the game?

I'm pretty sure there's a 9 somewhere... Just can't remember where.

I'm not sure about nine: The highest I've ever encountered is a 6, but i always play with ten INT.
(It's supposed to be realistic )

I think the highest is 9 but I'm not sure.

The highest I remember is 8 and that's from one of the routes you can take when dealing with the Legion Centurion. Haven't seen a 9 myself.

I have encountered a 9 INT speech option somewhere. Don't really remember where.. if I had to guess and probably be wrong I'd say it's something relative to Arcade Gannon, since he's such a smarty pants.

I've seen an intelligence check of 8 when interrogating Silus. I haven't seen higher than that yet though.