My local spot is always gusty and the wind nearly always builds when you're out. I find the 9 wave pretty good in the gusty shyte. But once it gets overpowered it's like riding a Lithium

I see why some people like the Lithiums, but they are not my style. I prefer something you need to work, not just pull the bar in and you have power. Sure it works for some riders style, just not mine
If you already have Lithiums and your middle kite isn't one, then maybe it should be?
If you are looking at changing the lot over a period of time, then maybe start replacing with the 9 Wave?
I don't unhook, but I believe the 9 Wave does it well.
The 9 wave isn't just for lighter people, it works well for us heavier people as well. It's my most used kite. I try and use it whenever I can, even if I am underpowered
If you're into boosting and unhooking, then maybe you need a Varial X as they do handle wave conditions well. Not as well as a Wave kite tho'
Jumping with the Wave 9 is not as brutal rip you off the water like the Varial X, it offers a nicer longer glide down. The Varial X is pretty good too tho'