I’ve read about “high wake” to avoid their gravity influence but I’m not sure what that means exactly.

When you drop out of SC, plot a route to another star system. Then FSD won't be slowed down by the mass of ships nearby

But in my experience the best is to just get good in escaping interdiction. I mean winning that mini-game with blueish tunnel. It's definitely doable in a T9. Also, that ship has better yaw than roll, so switch to pitch&yaw scheme. You don't need to be roll-aligned to anything to win interdiction game

Just in case you don't know: setting throttle to 75% (blue marker) gives best maneuverability.

Also I think with that money you could buy a panther clipper for higher profits by now.

Win the interdiction, which may be difficult in a type 9 but can be done.

Better shields and hull will help you survive, and to a lesser extent, thrusters. Military hull and shield boosters. Then engineering them will make you nearly invincible from NPCs.

Other alternatives include the Panther or the Cutter (faster, strongest shields).