I ride a 1x9 (Novara Buzz). If your chain is "jumping" off the front chainring it could be the chainring needs replacement. The only drawback, so far as I can see, with a 1x9 set-up is that moving the chain from 1 to 9 means a pretty severe chain angle, which, over time, wears down chainrings at a faster rate than you would with a double, triple or FG/SS.