As the transition point between middle school and high school, ninth grade can either set a student up for long-term success or diminish a student's likelihood of graduating high school altogether. Interventions that can help educators better meet the needs of students during this critical juncture represent powerful levers for driving school improvement. The Ninth Grade Success Initiative is a dropout prevention program, piloted in five Washington State high schools in 2019-20. We use multiple methods to evaluate effects on student outcomes and implementation processes. We find that the program led to improvements in course grades and, to a lesser degree, behavioral outcomes, with little change in student attendance. Data coaches perceived that this program led to more effective targeting of services to higher-need students and better preparation for the COVID-19 transition to virtual learning.