That depends on the current rating of the timer, and the current rating of the heater. if the heater doesn't consume more amps (watts) than the timer says it can handle, you're good to go. You may have to turn the heater down to a lower power output, if it has that capability.
My preference for heaters is electric radiators. They don't make any noise, especially compared to the desperate racket of those little ceramic heaters. In order for a heater that small to be able to deliver a decent amount of heat, they have to run their fans pretty hard. And I've had a couple of ceramic heaters, but they don't often have different levels of power, only an adjustable thermostat. They go full power to the set temperature and then turn off.
An electric radiator will usually have two or three different levels of output (the one in my bedroom: 500, 1000 and 1500 watts). Almost any timer you might have, even the ones designed to just run lamps for while you're on vacation, will handle 500 watts. That's just over 4 amps. It won't heat a large space, but if you're just looking for a bit of supplemental heat especially in a room not much bigger than about 12x12, it can be pretty good.
And it doesn't make a sound.
Good luck with it.