If you are worried about your children’s safety, please keep in mind that a cats give off very distinct body language that you and your family should learn. If your cat does not want to be picked up or petted anymore, you can tell! The more the tail is moving, the more agitated the cat and therefore the cat should be left alone. Also, if a cat’s ears are back and/or eyes are dilated (but you are in a well lit area), the cat is on high alert and likely will be easily startled. And this point is rather obvious, but your children may not realize it: if the cat is hiding leave him alone! He wants to be alone and will not be happy if disturbed. So teach your children to look for these signs before they approach your cat(s). That way, no scratching or biting will occur!
Side Note: Another topic to discuss with children (and visitors) is that most cats do not like to be held or picked up. They do not like to feel confined and therefore will struggle if handled. So make sure everyone understands not to pick up or hold down your cat!