At first the the BoolValue's value is false and without changing its property it changes to true.
game.Players.PlayerAdded:connect(function(player)
local Folder = Instance.new("Folder",player)
Folder.Name = "BoolValues"
local bool = Instance.new("BoolValue",player.BoolValues)
bool.Value = false
bool.Name = "BoolTest"
local ds = game:GetService("DataStoreService"):GetDataStore("user"..player.userId)
local DataLoaded = ds:GetAsync("Test")
if DataLoaded == nil then
DataLoaded = ds:SetAsync('Test',true)
end
bool.Value = DataLoaded
end)

2 comments
You do not get a data store per user, you create a key per user.
Also note that SetAsync does not pass back any value.