Highway 9 improvements for bicycles get funding approved
The thing to remember about bikes on mountain roads is that all non-wuss cyclists can descend at the speed limit. Whereas, even really good Olympic-class cyclists probably will be decidedly slower than the speed limit going up.
Hence, in theory, you only need to make wide shoulders on one side. However, if you do that, you'll rapidly discover yourself being knocked down while riding up by somebody who's brave enough to descend a hill at 35+ mph but not brave enough to do it in traffic. So I'm sure that they will probably end up having to add more shoulder than is strictly necessary. But the CA-9 needs shoulders in the zone between Skyline and Saratoga. I tend to avoid riding up it, just down.