Just looked it up on Surly's website. I like the simplicity of a 1x9 drivetrain. I'm hoping to build something similar myself for a commuter in the future.

As far as I know, the only think you need to worry about is making sure the BCD on the new chainring matches the BCD on the crankset as already mentioned, and then you might need to take a few links out of the chain, which you can easily to yourself. I think that should be it.