In this post, Optiphen revisited, I note that I think it's safe to say that Optiphen is suitable for anhydrous creations, so it should be good for sugar scrubs. But the bigger question is this: Is a scrub anhydrous? Kinda. We make them anhydrous - oil based or emulsified, there isn't any water in it - but it will be exposed to water, so we treat it more like a hydrous product when it comes to preserving.
In this post - Debate: Water soluble or oil soluble preservatives in a scrub? - it's argued that we want something that is both water and oil soluble in a scrub, which is a great idea. As Optiphen contains ingredients that are oil soluble and water soluble, it seems to be a good choice.
No, sorry, the preservative chart wasn't updated, but it's on the never ending list of "things to do" around here.