I'd vote for light orange. he's a good looking puddums!!!
(In cat breeding vernacular, I think he would still be termed "red", but I will let someone with more knowledge speak to that.)
I'd almost have to see him in person - but based on the pictures, I would call him a dark CREAM (buff color is "cream") classic tabby. There's a fine line between what breeders call "pale Red" and "hot Cream". You'd have to know the parents and the genetics.
If your cat's parents are dilute color cats, then he would be cream. If one was dilute and the other a non-dilute (meaning a black or red cat), then its an iffy thing as to cream or red.
Here's a picture of a cream tabby - and your cat does seem to be about the same shade
I would defer to GoldenKitty on this subject. I'm sure she can tell you whether or not cats colors do darken as they age. I know that's true with pointed cats. My neighbor's orange boy's color has deepened and darkened since he was a kitten.
If he crapped on her head looks like she would be in trouble then as they crap like every five mins lol I never even thought of it! lol
I found him as a kitten so I have no idea who his parents are or where he came from, he is the tallest cat I have ever had though! Hes as tall as a fox!