Can a MacBook Pro13-inc, 2.9GHz Dual-core Intel Core i7 use CL9 memory reliably?
Personally, I wouldn't risk buying anything that is not explicitly supported. You may run into problems in the long term if the memory modules draw too much power or are too fast/slow. 

You may want to check corsair.com/en-us/…, a 2x8GB memory module pack with 11-11-11-30 CAS timing (that is, CL=11, as Apple recommends). Corsair states that their "memory kits are tested at Apple Developer Compatibility Labs and work with most MacBook® Pro, iMac®, and Mac mini systems shipped in 2011 and newer." 

Since you mention in a comment that you plan on installing 16 GB while Apple only officially supports 8 GB: I bought 16 GB for my MacBook Pro (15-inch, Early 2011) and it works like a charm, although Apple's documentation states the maximum installable memory is 8 GB. 

Since my Mac has a non supported configuration, if I go to a Genius Appointment in an Apple Store I consequently replace my non-stardard modules with the original ones.

To summarize:


Stick to Apple's specs (speed, type, voltage, format, etc).
If other people confirm that more than the supported amount of RAM works, it is definitely worth a try. It will either work or fail, but it won't burn your computer's motherboard of anything. See this question at superuser for some opinions on this topic.


(Disclamer: I'm in no way affiliated to Corsair.)