The CyanogenMod team released the RC1 version of CM9 just before Google I/O started. A couple of weeks later, RC2 was launched, and now it seems that CyanogenMod 9 stable is trickling out for some devices. Well, truth be told, they've only released it for the Galaxy Nexus so far, which may be why the team hasn't made an official post about it yet. I'm sure that once at least a couple dozen phones will support it, they will announce it.
Reaching the stable version of CM9 is a very big deal for the developers that have been working on it for so long, because it has been a huge project. When they started porting ICS over, they've had to basically rewrite the whole CyanogenMod ROM from scratch. That has taken them since November of last year until now.
That's quite a lot of time, but it also explains why Android manufacturers took so long to upgrade their own devices from Gingerbread to ICS, as well. Hopefully, it will be a lot easier for them to port Jelly Bean and future versions of Android to their own devices, especially now that they will get access to Google's PDK.
Now that the CyanogenMod team is pretty much done with the CM9 ROM (there may be a CM9.1 and CM9.2 in the future), they can start focusing squarely on CM10, the Jelly Bean version of the ROM. The CyanogenMod team has already announced that some devices will not be getting CM9 and CM10, but otherwise most devices that support CM9 will be getting CM10. Hopefully, it won't be too long from now, and way before another version of Android is released, so the CM team can take a well deserved vacation.