The three volume set CCIS 2834-2836 constitutes the proceedings of the 9th International Conference on Computer-Human Interaction Research and Applications, CHIRA 2025, held Marbella, Spain, during October 2025. The 21 full papers and 64 short papers presented in the proceedings were carefully reviewed and selected from 106 submissions. These papers focus on the research advancements and practical applications within various areas in the field of Computer-Human Interaction, including Human Factors and Information Systems, Interactive Devices, Interaction Design and Adaptive and Intelligent Systems. The papers were organized in topical sections as follows: Part I: Human Factors for Interactive Systems, Research, and Applications; Part II: Interactive Devices; Adaptive and Intelligent Systems; Part III: Interaction Design.