I Would say so, but I would recommend a match ball as they are better quailty that is still only a training ball so it wont be the best.
problem is no proper sports shops anymore to go and get and actual feel.
Whats the point if he cant control or kick it properly? retarded.
Get something the right size and weight and practice technique, obviously at the age of 6 its all about fun so hes going to want something he can shoot with, give a 6 year old a size 5 and the balls going to go about two foot.