8 year old is old enoug for a sharp knife with a point.
Opinel was both of my boys first knives. Because there is no spring to overcome. No need for strong nails. No snapping closed with spring tension. Very easy to sharpen (I'd recommend their stainless over the carbon steel. Just as easy to sharpen, but holds an edge longer, and is basically maintenance free).
After the Olinel, both boys got a Buck 110 and matching 120 (the 120's are overkill, but I always wanted a 120 as a kid, and they came in a matching set).
Also bought each a small Cold Steel neck knife, and the younger uses that knife more than all the others combined.
Now they each have slipjoints, now that they can open them (older about to turn 16, younger is 11).
My first real knife was a Old Timer medium stockman.
Then a multi tool folder made in Japan (with knife, flat and Phillips head screwdrivers, small saw, cork screw) in a belt sheath for camping.
Then a Buck Light lock back for something light and locking.
I bought my first custom knife at 12 years old!! Lawn Mowing money well spent!! Still have that knife!!
First question, is what is your budget??
That will determine my real answer.
Locking vs non locking and stitches and learning the hard way are all relevant.
I learned that trimming nails (like Grandpa does) with his knife, when he is not looking was a bad idea (the amount of time it takes for a nail bed to grow out past the cut tbrough the nail bed with said knife is educational).
The severity of a cut that you can get while trying to force a locking folder closed without understanding the locking mechanism is educational.
Being cut while stabbing something with a non locking knife that shuts on you is educational.
Having a knife lock mechanism fail and being cut, is educational.
Having a fixed blade slip through your hand and sever a nerve because the lanyard caught on something is educational.
Trying to close an equal end slipjoint and pushing your finger against the sharp side, rather than the spine, because you are not looking (after having opened and closed that slipjoint a thousand times safely) is educational.
I've had a lot of stitches
I've learned a lot of lessons.
Getting a knife that your kid can't hurt them selves on is not really possible.
If it is a knife, they can find a way to hurt them selves.
I'm an adult, with 30 plus years experience with using, collecting and even making knives. I can still hurt my self...
Just buy the kid something useful, give him instructions, and tell him he learned a lesson when he cuts him self.....