Hi -- a PS is the safest way to go. If you're going to be there during a busier time of the year or want to dine during popular times (ie, 6-7:30), it's necessary. Saturday nights are commonly busy, too. This has become a very popular restaurant.
You can always make a PS and cancel if you change you mind. Then when you're at WDW you can call about getting a PS on short notice, if you want to be more spontaneous. If that doesn't work out, you'll have one to fall back on.
Definitely allow time to explore the resort and the grounds. They have a very nice shop with the typical Disney things and lots of African wood carvings, drums and musical instruments, artwork, clothes, etc. There's also storytelling in the evening, around the pit. Ask for a map at the front desk and find out where there's various places to sit outside on balconies in the large, hand carved rocking chairs.
Hope you get to see AKL and enjoy Boma's!