How to have different attribute values at the variant level


I need to store different values for an attribute depending on the variant.

I found a plugin doing the job :
But it is not updated since several month (not sure if it works on 1.9).

Is it the good way to go to add the attribute mechanism on variant or should I use option ?
If I go for the option way, how can I hide the option that should not appear as a select in the front ?

Thanks for your help