Mr. Rain Cloud
Does he not wash his film on the Patterson reels? I would think that any fixer would be adequately removed after having washed any film for an adequate length of time.
Lowering one's exposure index is the very first step to getting a more generous exposure. The OP has already told us basically how he meters...lowering the exposure index by one exposure value will lead to a more generous exposure even though he makes no change in his light metering technique.
Telling the OP to set his camera to 400 ISO when he is using Fuji acros 100 would be a massive step in the wrong direction. It is very important to read a poster's query very carefully. No matter what this guy does setting the camera to 400 ISO would cause massive under exposure.
I would tend to agree withyou that developing for nine minutes would most likely make an improved negative.