DIY motor driver

zoomkat:

Could you please point me in the right direction for finding a mosfet that can switch 9+ amps?

N-Channel MOSFET 60V 30A - COM-10213 - SparkFun Electronics

That mosfet will dissipate around 4W when passing 9A, so it will need a heatsink, which isn't ideal. I would choose a mosfet with lower Rds(on) such as IRLU8726PBF or IRLB8748PBF.