Is the Hajj of a child below puberty valid?

A child's Hajj is valid as a voluntary act of worship (nafl), but it does not fulfill the obligation of the Hajj of Islam. When the child reaches puberty, they must perform the obligatory Hajj again. This is based on the hadith of Ibn Abbas: 'A woman lifted a child and asked: Is there Hajj for this one? The Prophet (peace be upon him) said: Yes, and you will have a reward' (Sahih Muslim 1336). Sheikh Ibn Baz stated: 'The Hajj of a child is valid as nafl but does not count as the obligatory Hajj' (Fatawa Ibn Baz, vol. 16).