This book constitutes the refereed post-conference proceedings of the 9th EAI International Conference on Smart Objects and Technologies for Social Goods, GOODTECHS 2023, held in Leiria, Portugal, during October 18-20, 2023. The 13 full papers included in this book were carefully reviewed and selected from 30 submissions. They were organized in topical sections as follows: designing, implementing, deploying, operating, and evaluating smart objects and technologies for social benefit.