What day of the week are you leaving. Traffic much different on week days in the morning vs. on weekends.
Either way, a "safe" time to leave IMO would be 7:00 am. Without traffic/boarder delays it takes about an hour and 45 min. Say at a worst case scenario it takes you 3 hours (traffic, boarder delays). That's means you're at the airport at 10:00, then you still have a 2 hr buffer ahead of the flight.