Building Energy Tax Credit Act of 2009 - Amends the Internal Revenue Code to allow a tax credit for 35% of the cost of energy conservation commercial building property installed as part of a commercial building energy project within the jurisdiction of a state energy credit agency. Requires a building, to be eligible for such credit, to achieve an energy consumption rate of not more than 60% of the rate established by the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) Standard 90.11-2207 for commercial buildings.