well im sorry to say but surgical hogs are the best threestar strat vs th9s along with golaloon currently...
surgical hogs can three star almost any th9 base, but you just cant say that with valks. against a decent base design valks will just waste their time swinging at walls and eventually die out while nothing can stop hogs once the cc, aq, and dbgbs are gone, and with surgical hogs dbgbs dont even matter, but with valks, there are way too many variables to type that could stop them.
also with hogs the chance at threestar is way higher once you learn how to use them while valks can only three star certain bases, so if you confined yourself to valks you would only be able to three star aginst a small percentage of bases. with hogs you would be a better asset to your clan.
against th10s hogs are also a viable strategy to threestar with a couple of golems to tanks inferno beams, but when was the last time you've seen a max th10 get threestarred with valks...yeah i dont remember either:p.
i dont know when you last used hogriders but in the current meta valks simply dont stand a chance against them.
EDIT: heres a video showing a max th10 getting threestarred by hogs
https://www.youtube.com/watch?v=Ca0G6XKi2VM&t=2m30s