I think crampoons and a light weight ice axe would be prudent at this time of year judging by the pic in the recent Bugaboo tr. I have been there in mid September with ok weather. Of course the trip ended when it snowed a heap.
That weather link is a good resource to follow. Also, if you check out the 'chick on ice' TR you can get a sense of how much the cols are changing. If you're still thinking about the East Creek, weather may play a pretty huge role in success or failure. Something for nothing, I got word last week from some folks up at Applebee and it sounds like folks are wrapping up their projects for the season and heading on to other climes.
I was there two weeks ago.
It was iffy when using the B-S col. Rock falls on the right side are a big concern. There is a fixed rope to help you negotiate the climb up the col once you are over the crevasse/bergschrund (as of August 27). People are inclined to use the Pigeon-Snowpatch rappel route on the way down instead. Crescent spire and towers are good options to avoid afternoon rain/snow.
Have a good time and be safe. There was a fatal accident involving a father-daughter team before I got there. The father was the victim. Very sad situation.