It only means you have taken the course. The only kayak certification available is for kayak instructors. I moved here from the east coast back in November and I brought with me my Old Town Loon 120 recreational kayak. I need to get back out there, get my paddle wet and this kayak out of my garage in San Fran. Unlike sea kayaks, rec boats are not designed for rough water, even though you might get away with paddling them in rough conditions.
Most rec boats have inadequate floatation.
For these reasons, I would recommend staying away from the ocean and most of San Francisco Bay entirely. There are many calm water destinations inland, such as lakes, reservoirs, and flatwater stretches of rivers. But this will require some driving if you live in San Francisco. Here's a second opinion from one of our other experts regarding destinations for a recreational kayak. There are many calm, protected waterways in and around the Bay Area that are well suited for your recreational boating.