Well in short there is no way.

However if you have done backup from your CAL then you could in theory restore CAL from your backup. BUT before you get your hopes up, only Nokia employees with R&D certificate can backup&restore CAL areas, and all the people that could generate R&D certificates for N9 have already left the company.

And factory line jtag flasher, but its quite unlikely that you get access inside the production factory (and those factory lines are already ramped down anyways).

So in short if you happen to mess up your CAL, you can throw the device in garbage for spare parts and buy a new phone.