Student-to-School Nurse Ratio Improvement Act of 2009 - Amends the Public Health Service Act to allow the Secretary of Health and Human Services (HHS), acting through the Director of the Centers for Disease Control and Prevention (CDC), to make demonstration grants to states in which the student-to-school nurse ratio in public secondary schools, elementary schools, and kindergarten is 1,000 or more students to every school nurse to reduce such ratio.