Output capacitor current of boost converter
You're not plotting the capacitor output current, but you're plotting just the capacitor current. It is the capacitor's charge current (when the gate signal is low) and the decharge current (when the gate pulse is high).

When the capacitor is decharging this current is about -11.4A and equals the load current (in magnitude). The capacitor is decharging so the current is negative.
Exactly as shown in the simulation plot.