Thanks gents and I'm not quite sure which, but your comments have already been very helpful.
He has wanted a penknife for a while. The twin boys three years older than him directly across the street had penknives for their 9th birthday. The last thing I want him drawn into is (albeit natural), is either keeping up with the Jones' or one-upmanship.
I am therefore thinking that thanks to you chaps, I am leaning towards fixed blade. Such, just like my own stalking knife, only comes out (just like the .410 he will soon have), when we actually go out together and so therefore for strict specific purpose only. That then also remains consistent with the safety, responsibility and accountability I'm seeking to ensure is paramount, as his journey continues to the next level.
Whilst I agree the Mora is an excellent low cost and great utility knife, I'm not sure it's not just a little too large for his small hands and the job of gutting rabbits and de-breasting pigeons.
Thanks for all the suggestions though, I'll take a look through the links suggested.