@ Nitin
As per Section 3 of CEA, goods not mentioned in CETA imply non-excisable goods. So job worker manufactures non-excisable goods. The activity is manufacture has already been concluded earlier.
As per Finance Act 2009, amendment has been made to Finance Act, 1994 to exclude "manufacture of excisable goods" from the purview of Business Auxiliary Services, which implies that "manufacture of non-excisable goods" is covered under service tax.
Now, it can be argued why service tax on "manufacture" of non-excisable goods. That goes against the basic principle of taxing "services" and not taxing "manufacturing activities" under "Service Tax".
Personally my logic is, few reasons for including "manufacturing of non-excisable goods" under the ambit of service tax might be that, almost all goods are covered under CETA, if they are not it means they are either not goods, or not marketable, or immovable, or covered under some other Act, or not manufactured anywhere.
So, "manufacturing of non-excisable goods" implies providing service indirectly. Also, in real life, coming across a case where movable goods are not mentioned in CETA, yet it is a manufacture are extremely rare.
Also, basic principle is to avoid double taxation, but also to avoid NO taxation on commercial activity.
Registration will be required in this case under Service Tax as value of "taxable service" exceeds Rs 9 lakhs in your example. However, now Notification 8/2005 comes into play, because final goods of principal are excisable. In such an event job worker can still avail exemption under Notn 8/2005 and avoid paying service tax.
Now, you can modify your example - what if job worker produces excisable goods but such activity is not manufacture and principal produces non-excisable or Nil rated or wholly exempted goods?
In such an event, registration will be under Service Tax (because not manufacture), but Notification 8/2005 CANNOT come into play (because it applies only if principal manufactures goods on which excise duty is "PAYABLE").