My 8yo has had fuzz/darker/thicker blond hair for about a year. No changes beyond that in 12mo time. The hair on his head changed a bit as well. The last time this happened (hair changes) was at about 5yo. He got leg fuzz (still blond, but it's that different quality) and his toddler hair changed into "boy" hair.
At both of these switches (5 & 7) he also had a few months of time where he needed deodorant. Our ped says everything is normal. That kids go through hormonal fluctuations for short periods of time that make minor alterations to hair & skin texture (along with other things beneath the skin we don't see). But that these changes in no way herald puberty... just normal growth and development.
Continuing in his same growth pattern, I would guess the next O. to be at about age 9, and again at 11. Kiddo's been doing the repeat of the 'terrible 3's' thing this year (cognitive emotional integration), so it would make sense that hormones and glandular schtuff should follow. I've noticed the brain tends to ease kids into phases rather than do everything all at once.