I have used a Shop-Vac to empty a clogged garbage disposal. I, It was messy and smelly. I I seriously considered throwing it away.
It is nearly impossible to clean the corrugations in the hose. If the clog is human waste I would try a closet snake first even if you have to buy one. If its a toy or a rag or similar item you still don't know what else you will suck up.
On top of the mess in the vacuum you have to realize with out a filter you will potentially be spraying bacteria out the exhaust port hole.