Anyone know what integrated headset goes into the CAAD9 and where I can buy a replacement?

"FSA orbit si" is what the website claims, not sure whether they mean FSA orbit IS or if this is a headset made specifically for Cannondale (presumably this is not a typo, and the latter is the case).

I had this problem with a Specialized S-Works once, and I had to call the company, only to find out that it was, in fact, a Specialized-specific FSA headset that you can only get throught Specialized.

I found out it's the "Cane Creek" or IS standard - that is, 36/45 degree contact angles.

I decided to take a look at my CAAD9 headset for the first time. Reading this thread before starting, I expected to find the sealed-bearing 36/45 IS standard. Instead, I found my CAAD9 uses the 45/45 open bearing/cone system.

I had nearly purchased a 36/45 IS headset before wrenching, I'm really glad I didn't. And, instead of having to replace the headset, I could just clean off the bearings and other parts and repack it with grease and it's good as new.

So, in summary, CAAD9s us the 45/45 Campy Hiddenset standard. That is, unless there's variation within the CAAD9s, which I personally doubt.

Update: To clarify, nothing about the 45/45 standard demands loose bearings. Replacement parts like the Cane Creek IS-2i and IS-8i use sealed cartridge bearings. Whatever Cannondale spec'ed in 2007 was a loose bearing option. The important thing is that the contact angles are 45 degrees in both the upper and lower bearing.