This book constitutes the refereed proceedings of the 9th International Workshop on Economics of Grids, Clouds, Systems, and Services, GECON 2012, held in Berlin, Germany, in November 2012. The 12 revised full papers presented together with 6 work in progress papers were carefully reviewed and selected from more than 36 submissions. The papers are organized in the following topical sections: market mechanisms, pricing and negotiation; resource allocation, scheduling and admission control; work in progress on tools and techniques for cost-efficient service selection; market modeling; trust; cloud computing in education; and work in progress on cloud adoption and business models.