I created and printed (in PLA) some 9x6 propellers for my 800kv (4s) tricopter. Works well.

Warning:
Varying materials, print quality and more will make your print different from mine. It might break and throw knife sharp blades and harm you or somebody else. Make safe tests and make sure it will hold up for your purpose before you put it on a plane and go flying. I take no responsibility as to how these files/plans are used. Good Luck!