Jupiter mass is $1.9 \times 10^{27}$ kg, your creature is half of that.
Considering that Jupiter is already massive enough to perturb Earth's orbit, it;sit's safe to say that that thing should not get anywhere closer than somewhere between the Jupiter orbit and the asteroid belt, even though I am afraid that already its passing through the Oort cloud will cause a massive meteor shower toward the inner solar system, thanks to the jolt it will give to all the bodies orbiting there.
Past that the most likely effects will include disruption of inner solar system orbits, Earth included.