When I launch a daemon on my Macbook Pro, for 'daemonize" a python script, a python launcher icon popup in the Dock.
I would like to know if there is any ways to disable it / remove it
This icon : http://osx.wdfiles.com/local--files/icon:python/Python.png
To strictly answer your question, the application icon can be removed by setting LSUIElement to YES in the Info.plist for the Python application wrapper.
sudo defaults write /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/Info "LSUIElement" -string "1"
Should do it, but it will hide it for any Python applications. The changes can be reverted by substituting the 1 for a 0.
I also had to chmod the Info.plist file afterwards for some reason, not sure if that was just my configuration or what.