Pattern-based Refinemnt Generation Through Domain Specifi Languages -- Inductive Construction in B with the Theory Plugin -- Validation of Formal Models by Interactive Simulation -- Thread-Local, Step-Local Proof Obligations for Refnement of State-Based Concurrent Systems -- Encoding TLA+ Proof Obligations Safely for SMT -- Compositional I/O Abstract State Machines -- Crucible Tools for Test Generation and Animation of Alloy Models -- Modelling an Automotive Software System with TASTD -- TASTD a real-time extension for ASTD -- Validation by Abstraction and Refiement -- Verifying Event-B Hybrid Models using Cyclone -- Exploration of Reflectie ASMs for Security -- Standalone Event-B models analysis relying on the EB4EB meta-theory -- Adding records to Alloy -- Designing Secure Systems using Hierarchical STPA and Event-B -- Behavioural Theory of Reflectie Algorithms -- Specification in the Event-B Institution -- Verifying temporal relational models with Pardinus -- AMAN Case Study -- Analysis of a Safety-critical Interactive System through VOs -- Task Model Design and Analysis with Alloy -- Modeling and Verifying an Arrival Manager using Event-B -- Formal MVC: a Pattern for the Integration of ASM Specification in UI Development -- Exploring a methodology for formal verificatio of safety-critical systems -- Extending Modelchecking with ProB to Floating-Point Numbers and Hybrid Systems -- A framework for formal verificatio and validation of railway systems -- Reconstruction of TLAPS proofs solved by veriT in Lambdapi.

This book constitutes the refereed proceedings of the 9th International Conference on Rigorous State-Based Methods, ABZ 2023, held in Nancy, France, in May 2023. The 12 full and 7 short papers included in this volume were carefully reviewed and selected from 47 submissions. The proceedings also include 4 PhD symposium contributions. They deal with state-based and machine-based formal methods, mainly Abstract State Machines (ASM), Alloy, B, TLA+, VDM, and Z. .