At 8 years old it's not super normal for him to systematically refuse to go to school, so it's good that you have an appointment with the school psychologist. It's true that all kids have days where they drag their feet, but when it's systematic and he's making up excuses every morning, something's not right. The fact that he's saying it's too hard and that the other kids are making fun of him, those are signs that he's actually suffering, not just that he wants to stay home.
As for whether to force him or not, I'd say it's a balancing act. Of course you can't let him stay home just because he doesn't feel like going, otherwise you're just feeding his anxiety. But you also need to listen to what he's actually saying - are there academic problems? Issues with other kids? Is he sleeping badly, is he stressed? While you wait for the appointment with the psychologist, try to actually talk to him without making a big drama out of it, like just understand where it actually hurts, you know? And yeah, you gotta get him to school even if he whines, but like in an empathetic way, you know? Like "I know you find this hard, but we're going anyway" rather than yelling at him.
The school psychologist is really going to help you figure out if it's just a tough patch or if there's something more serious like bullying or actual anxiety. In the meantime, be patient with him but firm about the fact that he has to go. And try to create some nice moments before school, like a cool morning routine, rather than turning it into a battle.