Probably no need to worry.
The oil is still at the top of the motor and starts to drain when it is is shut off. The oil will take care of the heat.
The water temp does go higher but that's not really a problem as long as the cooling system is in good shape.
Generally, in hot months before shutting the engine off, I will rev the motor to about 1500 to 2000 RPMs to engage the larger cooling fan and get the water pump moving more coolant. I'll do this for about 15 seconds and then let it come back to idle before shutting off.
BTW: Don't do this if you have a turbocharger. Just let the car idle for 15 to 30 seconds.