This book constitutes the proceedings of the 9th International and Interdisciplinary Conference on Modeling and Using Context, CONTEXT 2015, held in Larnaca, Cyprus, in November 2015. The 33 full papers and 13 short papers presented were carefully reviewed and selected from 91 submissions. The main theme of CONTEXT 2015 was "Back to the roots", focusing on the importance of interdisciplinary cooperations and studies of the phenomenon. Context, context modeling and context comprehension are central topics in linguistics, philosophy, sociology, artificial intelligence, computer science, art, law, organizational sciences, cognitive science, psychology, etc. and are also essential for the effectiveness of modern, complex and distributed software systems. CONTEXT 2015 embedded also a Doctoral Symposium, and three workshops; Smart University 3.0; CATI: Context Awareness and Tactile Design for Mobile Interaction; and SHAPES 3.0: The Shape of Things. .