The youngest and only son of Herb and Bonnie Clutter, Kenyon's the least developed character in the Clutter family, but we know he's a happy, industrious kid. He's a bit of a lanky klutz, and:
This defect, aggravated by an inability to function without glasses, prevented him from taking more than a token part in those team sports (basketball, baseball) that were the main occupation of most of the boys who might have been his friend. (1.129)
But Kenyon's happy to be alone, tinkering with woodworking projects or his old truck. He has one good friend, who hasn't been around as much lately because he's got a girlfriend. He's sure that Kenyon will be into girls soon enough, too, but:
Kenyon doubted it: he could not conceive of ever wanting to waste an hour on any girl that might be spent with guns, tools, horses, machinery, even a book. (1.130)
We're told that Kenyon was…
Not in the least Mr. Clutter's son but rather Bonnie's child, a sensitive and reticent boy. (1.130)
Like the other Clutters, Kenyon's dead the day we meet him.