Reforming an Entitlement through Premium Adjustments based on Income Resources (REPAIR) Act of 2009 - Amends part D (Voluntary Prescription Drug Benefit Program) of title XVIII (Medicare) of the Social Security Act to require an income-related reduction in the part D premium subsidy.
Declares that, in the case of an individual whose modified adjusted gross income exceeds a certain applicable threshold amount for a month after December 2009, the monthly amount of the part D premium subsidy shall be reduced (and the monthly beneficiary premium shall be increased) by the monthly adjustment amount determined according to a specified formula.