Nope, cast on at least your normal 90. Ribbing does pull in; that's part of it's beauty, warmth, and practical nature.
I think it's worth doing a small swatch and stretching it to see just how much variation there can be in fit and appearance. It's width-wise expansion will also vary depending upon the type of ribbing, ie., 3X1, 2X2, 2X1, etc.
Knitting is more like tying your shoes than it is like patting your head and rubbing your tummy at the same time.