Sure, many times. I have juggled just about anything that can be tossed from one hand to the other, including my niece's 3 cats!
I have even done an egg, an apple, and a knife - and ate the apple while juggling them all.
A common stage trick is to freshly sharpen the blade to make it shine and then blunt the cutting edge. Leave the tip pointy, though, so you can pop a balloon with it to demonstrate how sharp it is and also tap the sides of the blades to show they are really metal.
One should be good with clubs before going to more exotic objects requiring rotation like knives. It is easiest to start with 2 easy objects like balls or beanbags and 1 exotic object.