Constitutes the refereed proceedings of the 9th International Symposium on Practical Aspects of Declarative Languages, PADL 2007, held in Nice, France, in January 2007, co-located with POPL 2007, the Symposium on Principles of Programming Languages.

QuickCheck Testing for Fun and Profit.- A Constraint Programming Approach to Bioinformatics Structural Problems.- Rewriting Haskell Strings.- Instantly Turning a Naive Exhaustive Search into Three Efficient Searches with Pruning.- Algebraic Knowledge Discovery Using Haskell.- Applications, Implementation and Performance Evaluation of Bit Stream Programming in Erlang.- Automatic Incrementalization of Prolog Based Static Analyses.- Verification of Java Bytecode Using Analysis and Transformation of Logic Programs.- Combining Static Analysis and Profiling for Estimating Execution Times.- On Improving the Efficiency and Robustness of Table Storage Mechanisms for Tabled Evaluation.- Compiling Constraint Handling Rules for Efficient Tabled Evaluation.- Prolog Performance on Larger Datasets.- BAD, a Declarative Logic-Based Language for Brain Modeling.- From Zinc to Design Model.- Inductive Logic Programming by Instance Patterns.- ARMC: The Logical Choice for Software Model Checking with Abstraction Refinement.- The Joins Concurrency Library.- HPorter: Using Arrows to Compose Parallel Processes.- Coupled Schema Transformation and Data Conversion for XML and SQL.- Aspect-Oriented Programming in Higher-Order and Linear Logic.- Partial Evaluation of Pointcuts.