Please don't "tailgate" an old topic. Your question has been split. I have included a reference to the original topic.
Now to what you mean. 9(9) is "numeric" - so are you saying you want it in such a format that it can be easily-read by a human? Or what? Please take some time to clarify your question. Remember, you know what you want, and we don't, so you have to explain what needs to be done, and what you have tried.
Your COMP PIC S9(9) is four bytes long. You specified it as six. Six is solely the output length that you want. Try the above in place of yours. You should be able to correlate the six-byte value you used to the six-digit answer you got if you do the whole thing as hex-to-decimal (see your PC's calculator) with the hex value you find in those six bytes. Bear truncation in mind.
As to whether you need to convert to compare, it depends. If you are using JOINKEYS, then yes, same length and type, start-position can vary. If you are just comparing in INCLUDE/OMIT/IFTHEN, then no, you don't need to convert. If comparing manually, then yes :-)