This book constitutes the refereed proceedings of the 9th International Conference on Software Business, ICSOB 2018, held in Tallinn, Estonia, in June 2018. This year the conference theme was "e;How Digitalization Impacts Software Business"e; and focused on digitalization and its impact on the speed of business models and business modeling and the realization of these business models.The 11 full papers and 1 short paper presented in this volume were carefully reviewed and selected from 34 submissions. They were organized in topical sections named: software ecosystems; software product management and business models; and software start-ups.