That's the most I've ever stated as well IIRC. Typically I just say NM-/NM or better. People are usually pleasantly surprised.
I will say "at least 9.6" at the most, although one time I did say "if there was ever a 9.8 candidate, this comic is it" - because it really was an easy 9.8.
I do wonder what it takes to get 9.9s... I have had a couple of absolutely immaculate comics come back as 9.8s. I am pretty good at grading the UHG stuff because IMHO, those are the easiest to grade. But a couple were, literally, immaculate. Corners sharp enough to draw blood with, no creases, no colour-breaking anything... the only thing is possibly something showing up under UV light. But I have yet to get a 9.9. I think CGC is a little protective of that and the 10 grade.
-slym
I will state "9.6/9.8" on certain books I list on eBay if there are no visible flaws on a book, especially if it comes from a batch/hoard of books I purchased all at the same time where I've previously submitted books for grading and have received only 9.6s and 9.8s back. But I would never state anything as a 9.9 or 10 unless it was a graded book.