Quoting MommyToWesley:" After looking it up, almost everything I found says that "cyn" prefix means chief for Welsh names. I ... [snip!] ... this website, though: http://babynames.allparenting.com/list/Welsh_Baby_Names/Kynan/details/ Maybe that's where OP got it?"
I found some info about it on several sites -- http://www.babynamespedia.com/meaning/Kynan is one of them
"There is no K in the Welsh language. "
I'm guessing the 'kyn' is a variation of 'cyn' that has been brought into the English language and changed over time, just like happens with a lot a Gaelic names (i.e. Cian becoming more common as Kian)