First, congratulations on your upcoming nuptials.
You are still within hurricane season so t possibility of rough waters exist. Carnival will attempt to to reroute the ship to avoid bad weather, if it arises. We encountered this in the Pacific once.
That said, most cruises go on without a hitch, even in September and October,
A Bad Day At Sea [with power] Always Beats A Good Day At Work
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, 2014, Caribbean 2013, Coral 2014