I have a softball size hole in the toilet bowl. Can it be temporary plastered or something. It starts at the water level.

No.
As a practical matter there is nothing you can do but replace the toilet.

I agree you replace it. They can't be fixed. Even temporarily.

Replacing it is easier and cheaper and much less hassle.

Most plumbers will give you a used toilet-free. I give them away on Craigslist.