Is it permissible to use Zakat funds to buy furniture or gold for a 9-year-old son, with the intention of marrying him off as soon as he reaches puberty, due to the scarcity of Zakat funds?

It is not permissible to withhold zakat for your son to marry him or to buy furniture for him, for several reasons: The son is not among those eligible to receive zakat, as his maintenance is obligatory upon his father. It is also not permissible for a mother to give zakat to her poor son, as his maintenance is obligatory upon her if needed. Zakat must be disbursed to the deserving immediately, not in the future.