I agree with the other posters. The action is long over at Tsukiji by mid-morning. If you are interested in visiting restaurant supply shops, then go, but otherwise, you have to arrive before 7AM to see significant numbers of fish on display.

If you want really good sushi, go to the tourist office in Narita town and ask them for recommendations. Every town of any size has an upscale sushi restaurant or two, and it's quite possible that the proprietor drove into Tsukiji in the predawn hours to buy the day's stock of fish.

Or, for one of those only-in-Japan experiences, go to the eel restaurant across from the tourist office, watch the guy sitting in the window skinning eels, and then have a delicious charcoal broiled teriyaki eel lunch.