GFCI for aluminum-wired house
Kill two birds with one stone.

Given the aluminum wiring, you really want AFCI breakers in the panel.  That will catch most aluminum wire failure modes.  Thing is, once you are committed to an AFCI breaker, an AFCI+GFCI breaker is only $10 more.

All breakers are Cu-Al rated, which is a standard for breakers.  This standard is fully modern and usable.  Not to be confused with the old, faulty Al-Cu rating for receptacles and switches which is what caused all the problems with aluminum wiring. 

Once you have an AFCI breaker, convert receptacles and switches to CO-ALR at your leisure. And done. 

Pigtailing

Yeah, you could put copper pigtails on the aluminum wire at the outlet.  However a couple problems with that.  First, most splice types have problems. Alumiconns are excellent if torqued properly, but they are both expensive and bulky, and the box is a tight fit already with a GFCI breaker.  You could end up needing an extension box such as a Legrand Surface Conduit Starter Kit.