In reply to goatee:
Trail shoes might be OK in fine weather, however they are more likely to get wet, and in a spell of bad weather you are not going to have a chance to dry them. In October you can also begin to expect snow.
Also if you go in October, it is 'fin du saison', everything is ferme. Refuges will be unmanned, and any bits you can buy on the trail will be limited as stock is run down for the close season.
Public transport is also virtually non-existant once you go past 30 September. You might be aware of all this, but if not it's much easier if you plan to be off the island by the end September.