There is a very detail thread about the "closed beta" testing of WeChat on N9: http://bbs.dospy.com/thread-14922572-1-464-1.html

I bet you getting headache when scrolling the whole crazy post right? Here, I help to highlight a few points:

- TS is a TX employee (TX is the company that developed WeChat)
- The thread is about closed beta testing of WeChat
- WeChat didn't officially release any build of WeChat of N9 to public, don't believe any website
- He said the beta testing of WeChat have finished in 31/7/2012 and expect to be available in Nokia Store very soon
- That post last update is in 8/8/2012

My conclusion: Dead project.