If Namine is Kairi's nobody and Kairi can wield the keyblade, shouldn't Namine be able to wield the keyblade too?

No because Namine isnt part of Kairi if you listen in Kingdom Hearts 2 on the computers behind DeZ (i think thats his name) and Ansem theres a computer with Soras regeneration + in the cut scenes theres a computer that says ''27% Regeneration) or something like that, also in it Namine said that Roxas and Sora are connected Kairi and Namine are not connected (Hope this helps) ~keybearer

No, because Kairi didn't initially have a Keyblade. In Kingdom Hearts II, Riku personally gave one to her, and at that time, Namine already existed.

I´m not all that familiar with Kingdom Hearts yet so don´t take me too serious but I guess theoretically Naminé should be able to wield a keyblade. Cuz she´s somewhat created out of Soras body and soul and Kairis heart or so and is Kairis Nobody. I don´t know if that matters but we all know Sora can wield a Keyblade. And since Kairi touched Aquas Keyblade once when she was a little child and still in Radiant Garden she can wield one too.
So you see theory says Naminé should be able to wield a Keyblade but I think it hasn´t been proved whether she can or she can not wield one.

Sorry if that is total bullshit but that´s it as far as I know

No, because they aren't connected really. But, Kairi should never had gotten that keyblade. She's useless, anyways, and I don't think that helped!

Never namìne created them all so,ha