I average anywhere from 8 to 17 MPH, depending on the day, time, weather, hills, etc, and just how I feel. I've ridden with riders who struggled to maintain 8 MPH and ridden with riders who averaged 19 MPH out of the gate, so it depends on the bike you ride, the gear you have to carry, your fitness, and the road conditions. Figure at least an hour to do the 9 miles to be safe and do a dry run. It will vary depending on traffic, weather, etc. Also plan on clean-up time as you may perspire and need to change clothing. Clothing may also mean saddle bags, baskets, etc, which all add weight and wind resistance, so too many variables to give you a good idea, but always plan on being slower than you think you might be.