I think it is anyone who takes Kurama's chakra. Recall Ginkaku and Kinkaku also have whiskers like Naruto. The brothers ate some of Kurama's meat when they were trapped in his stomach and gained some of Kurama's chakra.
Likewise, Boruto and Himawari also have a portion. Less, since they inherited it from Naruto.
Didn't I say the same thing? I did mention Naruto taking Kurama's chakra (due to possible interference), didn't I? (In case you think I overlooked this point)
And yes, I'm aware that anyone who takes Kurama's chakra by any means AND
makes it a part of his/her own chakra gets the whiskers. I didn't mention about externally receiving Kurama's chakra because I didn't feel it necessary to be added, that's all. I didn't deny it however. Anyway, thanks for apprising...
@bold They didn't get Kurama's chakra. They got Naruto's chakra
only. But since Kurama's chakra is a part of Naruto's chakra, technically the whiskers have now become a part of Naruto's genes. That's why Boruto and Himawari have them. If Boruto were to have an offspring, he/she would have whiskers too regardless of Boruto not having Kurama since a small portion of Kurama's chakra has found permanent place within Naruto's DNA and it will carry on.