Can I set a stop date for recurring tasks? e.g "every day until 10/9"
Unfortunately, that's not possible right now, but we may consider adding such option in the future. You're welcome to add your vote for this request in our Votebox: http://todoist.com/Vote/showProposal/214/
For now, as a workaround, if you want to complete a recurring task for the last time, you can right-click on it and choose "Move to history" or hold the SHIFT key while completing it which will have the same result (it will be moved to the completed tasks list at the bottom).