Not to speak for JoshC1977, but one of the big factors for 9 minute quarters and no accelerated clock was so the AI QB would make adjustments at the line.
There was also a lot of talk and testing last year that the game overall functioned better with 9 minute quarters. Fatigue through the course of the game being one the main positives. I have also heard that field degradation was better at 9 minute quarters.
Hope that helps.