I used to own that very chassis. I bought a new AX-9 at a nice discount because the X-1 had been in the market for a couple of years. It was better than my Sodikart SR-5 (all-32 chassis but without the narrow waist, had an archaic frame design, and was very stiff), but I struggled to match the pace of the drivers who had a 30mm chassis for the newly-spec D2 tire. I wish I had known that before I bought it.
Your AX-9 is all-32mm kart, and as such is stiff and produces a lot of grip. It was very good for a hard tire like the D1.
The X-1 that replaced the AX-9 is an all 30mm kart, developed because Mojo introduced the D2 tire, which was grippier.
My point in telling you this is to suggest that tightening a kart that already produces a great deal of grip is going to make the kart less flexible–perhaps unflexible–hence the sliding. I’m assuming, of course, that the kart isn’t worn out from years of use.
To me, everything you’ve done to the kart is making a stiff kart even more stiff.
Having said all that, T.J. is a lot smarter than me.