Renfe Cadiz Confusion, Please Help

[GJH123]

From our research, we have seen approximate walking times of 5-25 minutes from the Cadiz port to train station. It apparently depends on where the ship is docked and which gates are open. If we are the only ship in port can we count on a closer berth? Our ship is scheduled to arrive at 8:00; is there any way that we might make the 8:35 train to Seville? Where might we expect the taxis to be in relation to the ship (only at the gate) or closer? If we make it to the train station, is there any kind of security that we must go through before boarding or is it just a matter of jumping on the train if we already have tickets via the internet? On the renfe website, it lists tickets as being 85% refundable, does this mean that if we miss the first train to Seville, we are only out 15% of the ticket? Any helpful advice will be much appreciated.