In 2009, where were Bitcoin source codes stored? Now I can see the Bitcoin Core source code in Github but I wonder where the original source code of Bitcoin were stored back in 2009? Was it managed under SVN? How did contributors or programmers work together back then?

Thanks,
Pil
2008
We don't know if Satoshi Nakamoto is an individual or a group, but Satoshi Nakamoto asked for professional crypto geeks to review his project in 2008.
The original source files were therefore distributed privately through email.

2009
Unsure if Satoshi Nakamoto used any kind of source control before the source codes were available to the public. You probably have to ask the developers that were involved.
First available on Sourceforge.
Initial commits on GitHub were converted from svn on Sourceforge.