Excessive oil from the breather or draft tube is indicative of excessive blow by caused by bad piston rings ( worn out or stuck )
An engine that has seen too much dust or dirt will exhibit excessive blow by this condition is usually caused by an air filter system that allows dirt and dust to pass into the engine ( commonly referred to as dusting an engine ) .check for bad or incorrect or air filter or hole in the air filter hoses leading to the engine intake.
But before getting too carried away the first thing to do is as was stated earlier check your oil level as too much oil can also be the cause of oil dumping at the breather tube. From the little resource I've done it appears the C9. Has an oil capacity of 31.7 quarts not 34 if the engine is over filled the excess oil with be picked up by the crank shaft and flong up into the engine ( a phenomenon known as windage ) this causes oil to atomize and carried to the crankcase breather which is overwhelmed by the amount of extra oil and ends up passing it through the breather instead of scavenging it.
You need to make sure you are running the proper amount of oil.
The other thing you might want to do is service or replace the crankcase breather assembly as it's job is to allow excess crankcase pressure to vent while at the same time it is scavenging oil from that air it is letting escape if the breather is very dirty its ability to scavenge the transient oil is diminished and oil will pass through it and out the draft tube.
Here is a video of the replacement
https://youtu.be/xUY45wGWb-g?si=WStcrrwBy4vEIcLNHope this helps
Eric
