This book constitutes the revised selected papers of the 9th International Symposium on Formal Aspects of Component Software, FACS 2012, held in Mountain View, CA, USA in September 2012. The 16 full papers presented were carefully reviewed and selected from 40 submissions. They cover topics such as formal models for software components and their interaction; formal aspects of services, service oriented architectures, business processes, and cloud computing; design and verification methods for software components and services; composition and deployment: models, calculi, languages; formal methods and modeling languages for components and services; model based and GUI based testing of components and services; models for QoS and other extra-functional properties (e.g., trust, compliance, security) of components and services; components for real-time, safety-critical, secure, and/or embedded systems; industrial or experience reports and case studies; update and reconfiguration of component and service architectures; component systems evolution and maintenance; autonomic components and self-managed applications; formal and rigorous approaches to software adaptation and self-adaptive systems.