What you "accidentally" purchased is actually better than what was recommended to you. If you'll notice, the one you bought is CL8. The one which was recommended to you is CL9. For CAS Latency (CL), a lower number is better, as that means that it will run through less cycles to access the RAM's "column".
Just make sure to set the voltage right. It's rated to run at 1600 MHz, CL8, at 1.6 v.