The word “unique” means one of a kind*. Something either is unique (one of a kind) or it is not. There are no degrees of uniqueness. Something can no more be “somewhat unique” than it can be “very unique.” When people say “somewhat unique,” what they really mean is rare or infrequent. When people say “very unique,” I have no idea what they mean, and I doubt they do either.
*Incidentally, for those wondering, the term "one of a kind" should be hypenated when it is being used as an adjective (called a hyphenated adjective). For example, Erin is a one-of-a-kind friend.