The Massachusetts Non Compete Act specifically states that it applies to employees and independent contractors. That would suggest the short answer to this question is yes, independent contractors can be held to a non compete agreement.
However, separate from the Non Compete Act, Massachusetts law strictly defines the test for who can be legally considered an independent contractor. One of the tests the employer must meet is that you are customarily engaged in providing similar services to others.
On its face, this is inconsistent with a non compete agreement. This could lead to a situation where the employer is allowed to enforce the non compete, but in so doing proves that you should not have been classified as an independent contractor. If that is the case, you have a claim for misclassification damages that could be more significant than the non compete claim against you.