This book constitutes the thoroughly refereed workshop proceedings of the 9th International Workshop on Structured Object-Oriented Formal Language and Method, SOFL+MSVL 2019, held in Shenzhen, China, in November 2019. The 23 revised full papers included in the volume were carefully reviewed and selected from 43 submissions. They are organized in the following topical sections: testing and debugging, formal verification, problem solving, software analysis and evolution, and software analysis and testing.
