Possible rational zeros include factors of -9 (which are 1, 3, 9, -1, -3, -9) divided by factors of 7 (which are 1, 7, -1, -7). Therefore, zeros to test include (1, 3, 9, -1, -3, -9, 7, -7, 1/7, 3/7, 9/7, -1/7, -3/7, -9/7). Using synthetic division, divide the polynomial by each of these 14 numbers, one at a time. x=1 should give remainder of zero, which means that it is one of the answers. Try dividing that quotient by one. If that also yields no remainder, x=1 is a zero with a multiplicity of 2. Keep dividing by 1 until there is no longer a remainder of zero.
To find the y-intercept, plug in zero for x and then solve for y. You should get y=-9.