I do not feel that there are limitations upon this quality expressing through children. In some cases as a child I had many of the symptoms of Kundalini and none of the validation from parental figures for the condition. So validate their experiences and do your best to discern the truth.
I advise that as a parent who is in a Kundalini process you make yourself familiar with the symptoms of Kundalini awakening. As soon as you feel the child is communicating to you, with out prompting by you, at least three of the major symptoms, you begin to gently explain to the child what possibilities exist with regards to the Kundalini. The butterfly and the caterpillar are accurate and positive analogies in my humble opinion.
As far as encouragement allow them to be happy and interested in this development. If they are having OBEs allow them to understand about their guides and how to communicate with them. Allow them to know that they are very strong and powerful but in a way that is beneficial rather than dictatorial.
Explain about the chakras and the nadis and that spirit and body have unique qualities. As they are less likely to have present life issues they may have some past life issues and memories and those are to be honored though be aware of being manipulated by the child wishing to tell you what they feel you may want them to say. They can also be quite telepathic so be advised about your own inner dialogue and desires.
You will have guidance in this regard as will they. Following the intuitive path that will gently expose itself as is appropriate to the individual will greatly enhance and allow for trust to be established by you and the child in this process.
Share, communicate, honor, love, understand, and educate. Seek your own divine guidance or with those in whom you have an established trust. Show children the joy of discovery and help them understand the importance of discretion with regards to whom they discuss this with; make it private between you and them. - my take on this subject - chrism
Allow them to know that they are very strong and powerful but in a way that is beneficial rather than dictatorial.