When a pin needs to stay LOW or HIGH, is it okay to connect directly to VCC or GND?
It is usually fine to directly connect inputs to either GND or VCC. The datasheet of the device should be clear on that otherwise.

However:


when using devices like microcontrollers that have tri-state pins that can be configured both as input or output, then it is good practice to use a resistor (eg. 1k) to prevent the GPIO pin from being overloaded when accidentally being mis-configured.
when pulling for example a RESET pin inactive without a resistor, you can never activate it without changing the circuit. If you had a pull up/down resistor in place, you could manually override it.