I do not think that freezing a fish whole is such a good idea. I do a lot of late fishing myself and I hate to clean them at midnight myself. I like to out them in a cooler with a full bag of ice and leave the drain plug open. the fish will stay fine for at least 24 hours as long as there is planty of ice in the cooler. O also like to put a wet towel over the ice and it seems to help slow down the melting of the ice.
The sooner you get the orfal out of them the better Like Gitzit says cover them with ice don't just put the bag in there. Put some fish in add ice than a layer of fish more ice. Surround the fish with ice. Try and get the guts out if you can than filet them later. Doesn't take long to gut them. You want them to be yummy not yuckie.
If you are going to use any of the saving techniques listed here I would definitely bleed them before bringing them home. Just cut the gill plates and leave your live well running and draining for a while as you motor home and it will remove most of the blood from your catch. This is a good thing to do even if you are going to clean and filet walleye right away too. It eliminates a lot of the mess.
When we fish at night early in the season I will just leave them in the livewell and they usually always live until morning. Later in the season I put them in a garbage bag and throw them in the garage refrigerator and then clean them the next day. They always turn out mighty fine!!! Also, I have went to using the electric knife for all my filets now. So fast and clean it's easy to filet a limit in a matter of minutes.