Can I safely use my MacBook Pro HDD late 2011 with a late 2009?

I have a GPU issue with my MacBook Pro late 2011 which requires 3 weeks in repair (until the required parts come in). I took out the hard drive and put it in an external casing.

Can I safely use this hard drive on another MacBook Pro (late 2009) and still use my data/applications/OS X?