I have PCM variant of MC9090. when i connect it with windows PC it detects Com port which provides AT command interface but it is not able to detect sound card/PCM interface. does it require specific driver for sound device? if yes, where can i find it?
The PCM interface is used for audio. A few dedicated pins on the module is sued for audio, see PTS.
So you would need a PCM codec connected to the module to be able to use audio.
So there is no audio over the USB interface. So there will not be a USB sound card available.