It has been a long time since I was living in NJ. I believe traffic is heavy in spots around English Town and possibly New Brunswick. (I some times get route 1 and 9 confused because they are together in parts) If I were you, I would go to google maps, go to satellite images, zoom in, and see if it has a shoulder. On some of the maps, if you zoom to the lowest level, it has a view as if you were on the bike riding. It is very cool. The problem is, I am not sure that Route 9 has a shoulder, all the way. The other problem, and I would check with Adventure Cycling or AAA Road Club, as to whether there is construction on parts of it. In New Jersey I think they do construction, on the roads, whether they need it or not. I would be curious what you find.