H1B Extension Traveling Back to India - Please suggest


My H1B visa is expiring on 30 Sept 2015 and I have filed for extesnion and i have received acknowledgemnet number also but i need to go travel back to India before september.

  1. Can i travel back after receiving acknowledgement number ?

  2. Is there any risk, like will they reject my extension as i am not in US?

  3. If my extension goes void because of any of the above reasons how should i extend my H1B visa after reaching India?