If you're hungry after the flight and drive, you can eat at the mall where the Target is located. Several restaurants right there (there's a Ramen restaurant there that's quite good and reasonably priced, and they included pot stickers with every meal). If you've got the energy, just do your shopping then, quick and easy. As another poster mentioned, if you're too fatigued, then check into Aulani, relax and enjoy the resort, and save the shopping for the next day. We also stopped by the Costco a few blocks from Target to stock up on groceries (fruits, eggs, milk, frozen juice bars, etc.).
By the way, we started our trip off with the breakfast buffet our first morning at Aulani, and ended with the dinner buffet on our last night. Everyone felt this was a great idea and really enjoyed the food (much better than our last trip, so they've really been improving in this area). During our stay, we also ordered Pizza from Ulu Cafe and saw lots of people doing the same.
Have a great trip!