My first reaction was that the glue is sticking along the sides of the button. If you could manage to free the sides of the button from the surrounding case material, the problem would be fixed. Acetone applied to the outside can not get into where it needs to work.
To free up that button, it needs to be opened up by someone who does that all day every day. Like my colleagues, I strongly recommend taking it to an Apple-owned store, where that is exactly what they do!
It will be the most interesting problem that have seen all week, and they will fall all over each other to see if they can get it unstuck.
Remember at the Apple store, there is no charge for attempting to make you a happy customer by solving this problem -- unless it uses some parts.
Ii this glue essentially "super glue" ? it might be called cyanoacrylate ? If it is, Acetone will NOT dissolve it, only make it a little softer while wrecking everything absolutely it touches.