I'd have to actually look at the policy, but I don't know that insurance would be any more effective during hurricane season than not. It does cover trip delay, so if a hurricane made your flight late so that you missed the ship, it would probably cover
that.
Hurricane season will affect the cruise itself in that the ship may be going to alternate ports, or it may have to skip a port. In that case, I don't think insurance would do anything for you. The cruise line may or may not give you some kind of reimbursement.
We were re-routed to Key West (instead of St. Maarten) on our Sept. 2000 cruise, but got no compensation (nor did we feel we deserved any).
I think that insurance is most effective for medical care needed during the trip. Since the ships are technically part of the Bahamas, many domestic insurance companies don't cover treatment received onboard.
We've always bought trip insurance for our cruises. We've never had to use it, but you never know....