It is true that wands are attuned to wizards, as exhibited when Harry went to Ollivander's for his wand in the first book. We know, however, that Wormtail is able to effectively wield Voldemort's wand. He casts the killing curse on Cedric with it. For anyone to use the killing curse, he has to be a powerful wizard in his own right, something that nobody seems to think Wormtail is, and I seriously doubt he put on a show of ineptitude throughout his life just so people would underestimate him. I'm not going to subscribe entirely to the whole lost day theory, but I have always believed we do not know everything about the night James and Lily were killed. Someone had to take Voldemort's wand. Somehow the Fidelius Charm had to be bypassed so anyone could even find Godric's Hollow (I doubt Hagrid was told its location by Wormtail, yet he was able to find it). We may need a more thorough description of the Fidelius Charm to understand that.