I think if he is not out and out crying but just grizzling, I would say goodnight, or it's time to sleep or what have you and try and leave the room. Only going back in if he's upset or starts to cry. If he is too upset with you leaving you can try and comfort him with patting, etc. (I figure at 8 months you already have a "comfort" routine in place, still pat/shh etc) And if that isn't working you move to pu/pd. That's what has worked for us at any rate. If walking in and out works we do that but if it's particularly bad (and Ella is a horrible teether, always many night wakings) we have gone so far as to sleep on her floor for a few nights. But that's only been when she has become absolutely distraught at us leaving the room. If you stay consistent though it does pass! I hope that helps a little bit... keep me posted!
And loved the picture of Will sleeping btw!
Sharon