It is impossible to answer based on what you have written. It is not per se illegal to kiss and hug a minor (I hope parents do it as much as possible) but if this is someone who is attempting sexual or inppropriate contact with this child, then yes, they can get into trouble, fast.
The sort answer is: "It depends!" Many states prohibit touching a person's intimate parts. The definition of intimate part can include the buttocks, breasts, and pubes, or the clothing covering those immediate areas. The question then becomes, are you touching those intimate parts when you hug another person, to include a minor. If the answer is yes, you should probably think of different ways of hugging. A full embrace may not be appropriate, and borderline unlawful. You shouldn't take any chances with this. Perhaps you can consider a side hug where you, in essence, hug the other person's shoulders as you stand next to them. Of course, you should only hug anybody where it is pretty obvious that you have the other person's consent to hug.
The laws against unlawful sexual contact/assault have become very strict. If you are in a situation where you are around kids, you should observe, at least, the following few rules:
(1) don't allow yourself to be alone with any (stranger) child;
(2) if you are going to hug a child, do a side-hug;
(3) keep your body away from the child's intimate parts;
(4) When you do hug or have contact, strive to always have a witness around who observes your normal and appropriate touching of the child.
Pleae keep in mind that this response does not establish an attorney-client relationship. You should consult with an attorney in your jurisdiction to evaluate how the laws in your state impact on your interactions with minors.