I think in the end your cats name is whatever you feel fits your cat, but try saying Wakanda and get a feel of it. I know longerish cat names can sometimes be a drag to say so maybe try it out a bit before you decide? ^_^
It's a cute name, but may I ask, does it have significance for you, or do you just like the sound of it? I only ask because The Black Panther movie and Wakanda have a lot of symbolic meaning for many (an African country that was allowed to thrive without the history of white colonialism).
If you like giving your cat a name that represents strength, hope, and prosperity, that's pretty cool. But if you don't care about any of that, it could come across as trivializing something that's important to a lot of people. I think calling it "offensive" is too strong a word. It is a fictional place after all. But there aren't a lot of mainstream movies that celebrate black people and Africa like Black Panther, so some might view it as a little insensitive to take that and not be paying homage to the source material and intent. It'd totally be within your rights, but I just want to warn you that some people might be hurt by it.
If you do like the idea of Wakanda and what it stands for and want to honor that idea by naming your cat after it, I think that's a pretty cool name! My cat has a 3 syllable name and I don't find it cumbersome, although I do often give her other nicknames.
Welcome to TCS! Perhaps if you could post a pic of your kitten we could help give you some suggestions. And, yes, if you like the name Wakanda that is all that matters. Many of us spend a lot of time thinking about a name for our cats and end up using nicknames for them .