The compile error 9009 may also come in the flavor of error 22 or error 1 on projects with a post-build command. Sometimes it will even have multiple errors on the same item. What is happening can be generally found by cutting the post-build command out of the error summary at the bottom of the IDE and pasting it into notepad, removing the prefix and postfix data and then trying it in the command line dos-box.
Generally there are three main things that will mess up post-build commands...
1) bad path
2) a path with a .,:=[ ] in it
3) a path with a space in it
Because DOS 8.3 naming conventions still live under the covers of post-build command execution you can expect to get hamstrung by any of these scenarios. If you're developing under your personal workspace in windows you likely are being affected by number 3.
There is an easy way to deal with each of the above problems.
1) check your paths by pasting them into a File Explorer window
2) replace any of those characters with an underscore _
3) put your paths (even system named path variables) in double-quotations. "$(MyPath)\bin\debug\" for example.