SS/STT/XT/X all share a slightly "longer" frame. The steering angle is slightly relaxed and designed around a longer swing arm, longer seat rails. Short answer is no, not without modifying the seat rails to fit a short frame or vice versa.
The seat on the 9 on the craigslist ad was swapped for a standard seat. Take a look here to see what it would look like stock.
http://www.motorcyclespecs.co.za/mod...r9sx_cityx.htm
That price is not to special, you should be able to find similar at close to that price. I wouldn't worry about the seat to much, you can always have the stock one recovered to suit you for $100-$150. You may get an inch or two out of the seat, swap the bars for slightly taller aftermarket bars (limited to cable length) all with the goal of being comfortable for your 6'1" frame.