The last code I dealt with specified 6 feet as the maximum distance
between the closet flange and the vent. This was for UPC, I believe IPC
allows up to 12 feet. So, I doubt the 9 foot distance to your vent would
be too much of a problem.


In theory, you can get away with any value that's fewer
pipe-diameters than the inverse of the slope.

Meaning less than 48 pipe-diameters for a 1/4" per foot
drain. Which means you can draw a horizontal line
from the lip of the trap to the vent-openning.

SInce most codes permit anything from 1/2" to 1/8" per foot,
that would work out to 8' from trap to vent,
in a 4" pipe, but only 6' for a 3" pipe.

In practice, you want to vent as close to the trap
as you can, as long as you're far enough away to
keep flushing action from lobbing **** into the
the vent and plugging it. (Which I think is
supposed to be around 1.5 to 3 pipe diameters.)