Well, that looks way too complicated....which is why this is not a plumber's favorite brand. http://www.grohecatalog.com/product/34436/
But as with many shower controls which have dual function...meaning water control and temp control....it looks like he replaced the wrong part. The funtion of the wax cartridge is to pass water through, with the hot and cold balanced to desired temp. But bottom line, if water is offered to the wax cartridge, it is going through. That part is NOT responsible for water on/off, or in your case....water drip. Yes, the two stop valves, index #9, would be the problem. One for hot, one for cold.
I see a stop valve washer kit. I don't have any experience with this one to say whether it is worth the time to try an overhaul the stop. or just replace it.
O-rings can be greased lightly with waterproof faucet grease, available at any hardware store, or with silicone faucet grease, also from hardware and plumbing stores.