Can you deduct self employment health insurance premiums if you had a bronze plan, and if you only paid 8 of the 12 months?

Yes, for the months you had it.  You would have to reduce it by any Premium Tax Credit you received.   Also, the amount you can deduct is limited to your net profit in your business.  If your business has a loss, you will not be able to deduct the insurance premiums on the Form 1040. However, you can claim them as an itemized expense on Schedule A, if you have enough other medical expenses.

Here is where to enter your medical insurance premiums if you are self-employed:

https://ttlc.intuit.com/replies/4230299

Also, here is a link to a good article on Self-Employed Health Insurance .