E-FILING OF RETURN

If  you file the acknowledgement within 15 days of date on which return was filed on IT site, the date will be the date of filing on site. But in case if you have filed after 15 days , tha date will be tthe date on which the ITR V is filed.

In your case the date of filing the return will be 5 Jan 2009.

Yes thats right. The date of filing here will ordinarily be jan 5,09. However, an excuse can be sought for on the grounds of genuine reasons for the delay. 

Yes, both are right. Date of Filing of Return is 5th Jan. 2009 and the actions might be taken by the assessing officer for late filing of the return.

yes the date of e- filling 5 jan 09 and department  will be take action for late filling of return

yes date of filling of return will be 5th january

In my opinion the return filed on 15th Sep will be traeted as Null since you haven't submitted it within 15 days of e-filing & Acknowledgement will not be treated as true.