Were the provisions for air leakage changed in 2012 IECC compared to 2009 IECC?

Yes, in Section 402.4 of the 2012 IECC, testing is now required instead of an option between testing or visual inspection such as in the 2009 IECC.  Also, the air leakage rates changed.

Air Leakage Rates 2009 IECC 2012 IECC

Climate zones 1-2

<7 ACH @ 50 Pa

<5 ACH @ 50 Pa

Climate zones 3-8

<7 ACH @ 50 Pa

<3 ACH @ 50 Pa