These proceedings include selected papers presented at the 9th Workshop on Horn Clauses for Verification and Synthesis and the Tenth International Workshop on Verification and Program Transformation, both affiliated with ETAPS 2022. Many Program Verification and Synthesis problems of interest can be modeled directly using Horn clauses and many recent advances in the CLP and CAV communities have centered around efficiently solving problems presented as Horn clauses. The HCVS series of workshops aims to bring together researchers working in the communities of Constraint/Logic Programming (e.g., ICLP and CP), Program Verification (e.g., CAV, TACAS, and VMCAI), and Automated Deduction (e.g., CADE, IJCAR), on the topic of Horn clause based analysis, verification, and synthesis. Horn clauses for verification and synthesis have been advocated by these communities in different times and from different perspectives and HCVS is organized to stimulate interaction and a fruitful exchange and integration of experiences. The aim of the VPT workshop is to bring together researchers working in the fields of Program Verification and Program Transformation. There is a great potential for beneficial interactions between these two fields because: 1) On one hand, methods and tools developed in the field of Program Transformation such as partial evaluation, fold/unfold transformations, and supercompilation, have all been applied with success for the verification of infinite state and parameterized systems. 2) On the other hand, model checking, abstract interpretation, SAT and SMT solving and automated theorem proving have been used to enhance program transformation techniques. Moreover, the formal certification of program transformation tools, such as automated refactoring tools and compilers, has recently attracted considerable interest, posed major challenges.