I change short code: ?/./0/Dial/<blank> to ?/.S501001/0/Dial/<blank> where 501001 is the main published number (i.e. so the extensions do not present out their number).
Reading the manual, it does say that if the short code of: 9N/*67N/0/Dial/<blank> will block caller ID. This won't work in the UK (over here we dial 141) therefore the correct short code would be: 9N/141N/0/Dial/<blank> and this would stop all calls from presenting CLI.
You can create two short codes, the first to present the main number (used if people don't dial '9') and the second to withhold the CLI for people that do dial '9':
?/.S501001/0/Dial/<blank>
9N/141N/0/Dial/<blank>
Obviously the above are UK centric. Hope this helps,
J