sugar in rice milk?

I'm curious....I just decided to try some rice milk instead of goats milk but in reading the Nutrition Facts I found that there are 9g of Sugar per cup. Where does this Sugar come from? Here are the listed ingredients:

Filtered water, brown rice, gum arabic, expeller pressed high aloic safflower oil, tricalcuim phosphate, corowise thytosterol esters, Sea Salt , vitamin A palmitate, vitamin D2, vitamin B12.

Since "sugar" is not listed as an igredient can I assume that those 9g of Sugar are natural sugars?

Any input would be greatly appreciated, thanks.

Kasey Tweet