I don't think there is a difference between "proper" Kiswahili and a dialect, just as American English and British English are both "proper" but are different dialects of the same language. But the Kiswahili that I'm familiar with is from Kenya, it's where my family is from, and I've grown up speaking it at home even though I was born in the US.
If you're American, your name is an American name. There is no such thing as an "American sounding" name, even if some names are more common. All Americans are originally immigrants from somewhere else, even Native Americans. People that are now American come from all over the world.