Aloha Alyssa! Typically, September through to November are the slowest months, but Aulani is becoming so popular, not just with guests coming from far away, but also the locals, that there really isn't a time when it won't be too busy. Have no worries though - there are more than enough activities to keep guests of all ages occupied, whatever time of year you decide to go. There are often special rates offering a free night, so be sure to check their website for current deals.
For your little one, the Waikolohe Valley will surely be a hit. This is the central water area that includes the Menehune Bridge - water slides, play structures and water spouts galore - kids absolutely love it. Speaking of Menehune, one of my favourite activities at Aulani is spending time exploring the resort and trying to spot all of these mischievous little people hiding in the most unexpected places! Also, your child may enjoy spending time in Auntie's Beach House, a kids club for guests 3-12 that is packed with awesome activities.
Adults have not been forgotten either - the Laniwai Spa is a real haven, and an award-winning spa! The beach at Aulani is the perfect place to spend the day as a family - the water is gorgeous and calm, and perfect for swimming! In the evenings, there is storytelling around the fire with 'Uncle' - so much fun, and different each time. It is a must do, as far as I'm concerned. You also won't want to miss the Starlight Hui, which is the Aulani version of a Luau done Disney Style. So much fun for everyone, and it ends with a visit from some familiar characters.
Alyssa, this is only the tip of the iceberg of what
Aulani has to offer - I suggest checking out their website and really exploring all of the links to get a real feel for the types of activities for each member of your family.
Kristen