Spin or rotation while shooting a 35 gr bullet a near speed of light velocities does not work well with a nine twist. Spin is calculated as Velocity (FPS) X 720 / twist (9 or 12 in your case). I'll use a velocity of 3500 fps for this calculation keeping in mind it's probably a bit low.
Example: 3500 X 720/9 = 280,000 RPM , or 3500 X 720/12= 210,000 RPM.
So shooting your 9 twist and using a very conservative 3500 fps you can see that you are at or beyond the RPM limit for typical Hornaday bullets. Other bullets that are not thin skinned varmint bullets such as target bullets will have better RPM ratings, upwards of 310,000 RPM, maybe more.
Like the tires on your car, every rotational object has an RPM that it likes best. These are the harmonics, and if you are not spinning the bullet at it's favorite harmonic, it's not going to fly it's best.
My 9 twist seems to like the 53 V-Max and shoots it to extreme precision, while my 8 twist .223 prefers a 69 to 73 gr.
As always, your mileage may vary.