Half yearly return

No, because you have not raised any invoice after getting service tax before 30th sept and even your registration is starting from 7-Nov so you dont require to file any return.

In my opinion, you are required to file Service Tax return for the period April - September 2011. Though the certificate was received at a later date dated November 2011, it is not a good excuse for non filing of return. If we refer Rule 4(5) of Service Tax Rules, 1994 as amended it says that:

"4(5) The [Superintendent of Central Excise] shall after due verification of the application form, 2[or an intimation under sub-rule (5A), as the case may be,] grant a certificate of registration in Form ST-2 within seven days from the date of receipt of the application 3[or the intimation]. If the registration certificate is not granted within the said period, the registration applied for shall be deemed to have been granted."

Service was provisioned in September 2011, Service Tax was levied. Hence return for the same is required to be filed as per Service Tax provisions.