The chances of anyone making it look like something else now is pretty slim.
Banisters take a lot of wear and this one is the focal point of the entryway. Stripping the old finish and stain isn't easy or usually even possible since the stain is already deep into the wood. Even sanding the entire thing down to bare wood probably would still leave dark spots and light spots that would never match no matter what finish you put over it.
To tell you the truth you would be far better off learning to live with the lovely walnut banister, even if it doesn't match your kitchen cabinets. I take it that walnut or something like it just won't work for you in the kitchen?
The only other 'option' is to replace the entire banister with something that matches your tastes, because I don't think anyone will give you a guarantee that the refinished banister will look perfect.