Yes you can scoop the cat poop out of the litter box and flush it down the toilet without any issues.
I've always flushed the cat poop down the toilet after shaking off most of the cat litter and flushed the toilet a few times and it went down the toilet with no issues.
Just don't dump a bunch of cat litter down the toilet and you shouldn't clog the toilet.
If human poop can go down the toilet so can cat poop and it's a better way to dispose of it instead of dumping the cat poop into the trash can which smells.
I've also flushed my dogs poop down the toilet when they pooped on the floor because I can't stand to put poop in the trash can.
The same goes for when my kids were in diapers I would flush as much of the poop out of their disposable diapers before throwing them away.