הוצאת ויזה כשלבן הזוג יש ויזת סטודנט

You need to be married before your partner gets his/her visa I believe if it's a J1 then you get a J2 and can work to some extent I am not sure how much

do you know if we need to be registered as a married couple in israel or not?

you need to be married here if you want a derivative visa