Agree with you. The leaves color and the tree branching pattern is not characteristic of the Bael/Bilva tree but sometimes in young trees the leaves vary in size, color and pattern. A picture of a flower/s would have helped.
Interesting pointer by RS regarding the hardiness in subtropical. News to me. Thanks. Don't remember ever tasting the fruit and probably did not nor I have seen anyone trying to harvest the fruits for consuming. It is used for home remedies and some ancient Ayurvedic, Unani, Chinese medicines and other herbal medicines in Asia and Africa.
CarolinaZone : Just saw your posting about the white flowers. How many petals? Was there some aroma? The leaves may or may not have strong aroma when crushed. The fruit takes long time (7 months?) to ripen from this stage as seen in your picture. Thanks.