The period of September to September is odd. The reason I say this is because unlike European football leagues and in fairness, pretty much most sporting leagues around the world, there is no proper season for cricket. The official start of the English season is about March, for the Asian sides...i don't even know, it starts when ever they have an international to play and for Australia/SA/NZ it is the English winter, their summer. So why pick an arbitrary period, which is what September becomes.
Just having a full calendar year makes more sense and just by looking at the ICC, even their not convinced by the September date as the awards used to take in August at one stage too.
For all the stick FIFA have received recently, they really are a better model when it comes to scheduling things properly. The ICC is just way too hap hazardous.
Anyway that's my little rant on how the awards should be organised, although it wouldn't make much of a difference on picking Ashwin as player of the year but it would provide a better view of who has been a better batsman in 2016, and that's Kohli > Williamson. Cook also wouldn't get put in as captain.
Plus, like I said, Sep to Sep or Aug to Aug as it used to be is just arbitrary. Better to keep it a singular calendar date.