A rub does not mean that it is a buck marking his area. In fact, very few rubs you will find mean this. It could be that the area you have found is a stagging area where one or more bucks are holding up before leaving cover to go feed.
I don't know where you are located, but here in Illinois, I have been seeing rubs since the beginning of season, but have not found my first scrape yet. I would assume that any day now the younger bucks will start hitting scrapes. By the 1st of Nov, scrapes should be popping up every day, but just has not started here yet.