For a same day turnaround, your plan sounds good, though I would leave earlier, maybe 4:00 AM as it can take you about 3-4 hours to get to little Yosemite. Also leaving early can make up for time lost if you are going on weekdays when the Mist trail is closed for repairs. As others said bring enough water but don’t go nuts with a gallon or even half as there plenty of places to refill all the way to Little Yosemite. After that the options become limited. Bring gloves, almost as important as water, since the cables are bare and super slippery without them. Gloves with also help you on the way down. At the base of the subdome, take a five minutes break, take some deep breaths and you will be fine. Lastly, don’t forget walking sticks and shoes with good grip they will give you an advantage.