Hwy 9 is a local legend in the Santa Cruz mountains, and as a result it's a bit of a 'racer road' and as a result of that it gets a lot of police attention. Within the last year or two the speed limit on the section from Saratoga to the Junction with Hwy 35 has made almost absurdly low (30 mph, I think) to try to further damp the enthusiasm of riders.
What's the appeal? Well, the area is very pretty, and the road - for the most part - is very well engineered. Most of the turns are cambered so nicely that if you get in too hot, just roll off the throttle and the turn will save you. Quite the ego rush!
This road is close to major population areas (Silicon Valley), goes through beautiful, redwood studded mountains, and it links into many other great local roads. Keep an eye out for the local constabulary, and another eye on your mirrors for rapidly closing local hotshots, all while enjoying the scenery, and with any eyes you have remaining, watch the road. It's definitely a San Francisco Bay Area must ride.
A nice mixture of different low/medium speed corners and some straights.