Yeah KT was open, but the Saints dropped 8 into coverage and that might’ve been what made Brady hesitate. Looks like Brady saw KT too, but probably would’ve had to have thrown it earlier. 33 was in okay position to possibly jump the route. It would’ve been close. Brady was playing safe.
Really what they want to do in that situation is run the ball. If you watch NFL Turning Point they pointed out the same thing.