There can be some effect, but it's statistically insignificant and it's pretty doubtful you will see any difference if the real world. Especially with a 9 twist 7mm, which really isn't a quick twist (Remington uses a 9 1/4 twist in their 7mms).
For example, I have a 1 in 14" twist 223 AI, and a 1 in 8" twist 223 AI. They both shoot 40 grain Ballistic Tips at essentially the same speed, with the same loads. Both shoot really really well.
'Tis the beauty of the quick twist. There's no real downside.
