This book LNCS 15755 constitutes the proceedings of the 9th International Symposium on Model-Based Safety and Assessment, IMBSA 2025, held in Athens, Greece, in September 24-26, 2025. The 28 full papers were carefully reviewed and selected from 39 submissions. The proceedings focus on System Safety Assessment, Cybersecurity Analysis, Safe Machine Learning, Probabilistic Analysis, Model-based Design and Safety Assessment, Machine Learning and Automata Learning for System Safety, Failure Detection Isolation and Recovery Analysis.