Not every response above 5 on a 9-point scale indicates agreement - it depends heavily on the individual's interpretation of the scale.
That's why 4-6 is considered indeterminate - it's "in the middle"
In my opinion, anything above a 5-point scale is a bit of a stretch - I just don't believe that people can really distinguish a difference as narrow as 1 point on a 7 or 9-point scale, and people tend to not use the entire scale (sometimes even at 5 points).
At my place of work I send out an annual 5-point Likert customer satisfaction survey, and I have never, ever received a "1" on any question, ever.
The only exceptions to this might be a poll of subject-matter experts where the subject of the poll itself is their area of expertise.