CCLog output is shown in the console.
NSLog (from Objective C code) is not shown in the console.
More important:
AdMob SDK Console output is not shown (probably because it uses NSLog).
There is no such problem in pure IOS Objective C code.
Only in mixed code Objective C / C++, probably because the cocos2dx code takes control over the standard output.
How to enable console messages that are printed with 3rd party SDK using NSLog?
with 3rd party libs you sometimes have to set a flag to enable logging like -enableLogging(true) for example (some have different tiers of logging with different flags). Make sure the SDK is set to log, just an extra thought.