Toggling 9A with ATtiny85 single-button-latch
You can get MOSFET gate drivers, rated at 6 amps for 100 nanoseconds, to repeat 100,000 times a second. And some suppliers sell 9amp &amp; 12 amp gate drivers, in TO-220 heat-sink-tab packages.

None of these are for continuous DC currents  higher than 0.5 amps UNLESS HEATSINK.

They will handle 15 or 18 volts, and control a huge MOSFET gate.