I heard someone call Mike Phillips as a ninth forward and Ben Youngs as a sniping scrum half what do these mean are there any other types

That was possibly more of a description of the type of scrum half those players are. As you've got 8 forwards, they are simply describing Phillips as more of a forward type of player or hybrid since he's a small player but really bulky and strong. Whereas Young's and others like Genia, Smith - when they describe them as "sniping" halves it means they usually dart quickly and looking for holes everywhere like a good #9 should. But there isn't such a thing as different types of scrum halves

Phillips is a big bloke and charges like a forward. Youngs is much smaller and finds gaps by sniping.