One could argue he could tear her atoms apart through the Speed Force. After all, in DC, it's the source of all motion. But is it fair to enforce that rule with Kitty? If they were to fight in a comic, I would think Kitty would have to be under the SF's influence if Wally's powers work. But it's pretty iffy.
Sonic booms won't work. She survived the blast from the giant robit and it clearly had a major concussive component to it.
He can't carry someone into the speed force if he can't carry them can he? Maybe he can make the entry point inside her but whether or not it'd pull her in is speculative.
It kind of rides on if he can use his SF powers on Kitty or not since most of his powers are physical based.
On the other hand, what is Kitty going to do on Flash? Advance on him?