If you are at a Park at or near Rope Drop (or have early breakfast at Tusker House), then you might not need a FP+ for anything during the first hour or more.
With the possible exception of Belle in MK, Toy Story in HS, Soarin' & Test Track in EPCOT, having a 9am FP+ is considered a wasted FP by some bloggers.
If you can avoid using a FP+ that might otherwise be used for another attraction when lines are longer, then I would avoid using the FP+ first thing in the morning.
That being said, your needs, like mine, may vary. For instance, my child loves Flights of Wonder with first showing at 10:30am. Having an early Kilimanjaro FP+ gives me peace if mind that I can do a clockwise rotation from Kilimanjaro to Flights of Wonder to Everest to Kali Rapids to Nemo show.
In this instance, we use the FP+ early because we will be leaving AK on the early side of the day with no expectation of returning or utilizing FP+ in another Park. So I can either use a 'wasted' FP+ or not use a FP+. I choose using a 'wasted' FP+.
In other words, like many families traveling with small(ish) children, utilizing FP+ for the early hours you are most likely in the Parks makes the most sense. But if you can avoid this, utilizing FP+ at higher crowd periods in the afternoon would be the recommended use of a FP+.
