Does a voodoo doll worship the devil?

Not at all.

Practitioners of Vodou/Voodoo (Vodouisants) are highly spiritual people. They worship a supreme God (Bondye). And a number of other Deities/Gods (Lao), that represent different aspects of humanity and spiritualism. The Loa are prayed to, respected, worshiped and are spoken to as a means to transport one's prayers to Bondye (God).

Along with prayers and alters created in dedication to one's departed ancestors.