Sun had been defending wn pretty hard so his only options at eod were to not vote, or to vote Mac. Although he mentions that he could get away with not voting because he's often off-wagon as a villager, I don't think that can really be used in his favor... for precisely the reason that what he did is what he often doesn't do as a villager. And if he's a wolf, he'd be aware that not voting there to save his villager looks really bad even if he knows he might forget to vote as a villager.
He had bhuber as a wolf early, but ended up moving his vote around quite a bit. Not anything that's necessarily bad for him, but there's not much that can really be used to clear him on the basis of pushing wolves: he was pretty late onto the wagons of both bhuber and McAvoy.
No mention of bhuber until his final post, which was to put the fourth vote on.
It's not fair to hold Sun to a standard of leading lynches and such, and he did end up with his vote in the right place when it counted, and he didn't really do much that actually seemed wolfy.... but he was always really late in getting onto the wolf wagons. I don't think his voting record can be used too much in his favor.