I would rather have it taught to them first. Handing an 8 year old kid a Bible and saying, “Here read this and figure it out on your own,” isn’t really a helpful idea.
First, their parents should be catechized so that with the aid of the parish priest, teachers at their school, catechists at their parish, and most importantly the parents in the home can teach the Bible to the child through regular study, lectio divina and prayer.