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 “How Digitalization Impacts Software Business” 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.