I've done it twice, the first time the weekend after season close (about aug 29 iirc) and the second time around sep 5. I think climbing just out of season is a great idea as you miss the crowds however while almost all huts were open when we went up on the 29th the second time when we went in early sep only about a third were still opn. By october the huts will be closed and the weather will be getting worse so if you are planning a climb at that time I'd say you'd have to be prepared/ have the ability to cope with real climbing in snow/ice conditions and to be able to perform a self rescue.

Or to put it another way, if you're asking about it on a flyertalk forum it's a fair bet that it's beyond your abilities to do with a reasonable level of safety. A partial day climb should be fine though however make sure you check the closing time for the toll road otherwise you'll be in for a cold and not very fun night