The answer would be 3. The difference between the remainder and the divisor is 2, so the reminder would go down by 2 each time the coefficient of b increased by one(except once it gets to 7, at which case it starts over).
The sequence: 5, 3, 1, 6, 4, 2, 0, 5, 3.
The ninth number is three, therefore the remainder is three.