My format system was under mount and storage.. I tried several times last night to load CM9 with CWR from Rom manager. I finally flashed in fastboot the CWR for ICS 188.8.131.52 and then I followed this and everything went fine.
- Wiped the big 3. Factory reset,partition cache, then dalvik cach under advanced.
- Selected mount and storage. Format system=Yes
-Flashed the Rom
-Flashed the Gapps.
- Once logged in went back to recovery and wiped partition and dalvik cache and flashed the v9 kernel from aerovan.
-Boot up and enjoy the ICS.
Hope this helps!