This is consider a monomial since we only have one term. Terms are separated by a plus sign, so something like 5x^2+10x has two terms.
The degree of a polynomial is the largest exponent when dealing with single variables. In the case of 9r^9, the largest exponent is 9, so the degree is 9. Going back to an example like 5x^2+10x, the largest exponent is 2 so this is the degree of this example.
