Apache ProxyPass or ProxyPassMatch to exclude a file from proxying

I have a VirtualHost set to proxy all requests to another server running on port 9000.

What I have :

ProxyPass / http://localhost:9000/
ProxyPassReverse / http://localhost:9000/

What I've tried :

! ProxyPass /test.html http://localhost:9000/
ProxyPass /test.html ! http://localhost:9000/
ProxyPassMatch !^/(.*\.html)$ http://localhost:9000/$1 

None of which worked…

I'd like to exclude a file or a set of files from being proxied, the documentation says something about "The ! directive is useful in situations where you don't want to reverse-proxy a subdirectory.", but there are no examples for that situation.