You may want to try the Barnes X bullet. Not the Barnes Grenade, but the actual TSX bullet. They expand but do not come apart like the varmint bullets and due to them being long for their weight, you can get away with shooting a bullet that is not normally ideal for the 1:9 twist, such as a 45 or 50 gr. bullet
A 1:9 twist is for light to mid weight bullets, not heavy bullets. The faster the twist, like the 1:7, is best for the heavyweight 72-80 gr. bullets. 1:8 and 1:9 twists are excellent for the mid weight bullets from roughly 55 to 75 gr, while the old Colt SP-1 1:12 were ideal for the 40-55 gr. weights.
My 1:7 twist rifles do not like 55 gr. or lighter bullets at all with groups being about double the size as in the 1:12 or 1:9 twist rifles. The 1:12 Colt does not like the 72-79 gr. bullets at all either. The 1:8s and 1:9s seem to like everything except the really light 40-45 gr. bullets or the heavy 79s.
The groups are not terrible, just larger when the rifling twist is mismatched to the bullet, such as the 1:12 being a sub MOA shooter with 50 gr. bullets while the 1:7 is a 1.5 -1.750 MOA shooter.
My 1:8 bench rifle loves 69, 75, and 79 gr. bullets but for some odd reason will not shoot a 72 gr. bullet of any make, so that just proves that there are always exceptions to the general rule.