Strengthen the Earned Income Tax Credit Act of 2009 - Amends the Internal Revenue Code to: (1) make permanent the reduction in the marriage penalty applicable to the earned income tax credit; (2) increase the rate of such credit for families with three or more children and for individuals without children; (3) modify earned income tax credit requirements relating to abandoned spouses and qualifying children; and (4) repeal provisions denying such credit for individuals with excessive investment income.