Which ones are OK?
I have a kin there.
I have kin there. or I have kins there.
I have some kin there. or I have some kins there.

Question

Which ones are OK?
I have a kin there.
I have kin there.  or  I have kins there.
I have some kin there.  or  I have some kins there.

Answer

"Kin" is plural, meaning family or relations, so "I have kin there" sounds the most correct. However it is very formal, most English speakers would normally say "I have family there" or "I have relations there".