How to save data when the player leaves?

Heres the script that i have but when i print the datastore i get nil:

Script:

Data = game:GetService("DataStoreService"):GetDataStore("BlastOffMoons")
JSON = game:GetService("HttpService")
Tycoon = ''
local base
local corner
local placedItems = {}
game.Players.PlayerAdded:connect(function(Player)
	repeat wait(1) until Player.Character
	repeat wait() until workspace.TestTycoon.Owner.Value ~= ''
	if workspace.TestTycoon.Owner.Value == Player.Name then
		Tycoon = workspace.TestTycoon
	end
	local plrData = Data:GetAsync(Player.UserId)
	print(plrData)
	if plrData then
	for i, Object in pairs(game:GetService("ReplicatedStorage").GameItems:GetChildren()) do
		for e, Data in pairs(plrData:GetChildren()) do
			if Object.Name == Data[1] then
				local newObject = Object:Clone()
				newObject.Parent =  Tycoon.TestItems
				local location = tonumber(Data[2],Data[3],Data[4])
				newObject:SetPrimaryPartCFrame(location)
			end
		end
	end
	end
end)

game.Players.PlayerRemoving:connect(function(plr)
	if workspace.TestTycoon.Owner.Value == plr.Name then
		Tycoon = workspace.TestTycoon
		base = Tycoon.Base
		corner = Tycoon.Base.Position - (Tycoon.Base.Size/3)
		print(corner)
	end
	local playerData = {
	Money = plr.Money.Value,
	Placed = {['itemPositions:'] = {}}
	}
	Tycoon = workspace.TestTycoon
	for i, v in pairs(Tycoon.TestItems:GetChildren()) do
		print(v.ClassName)
		if v:IsA('Model') then
		    table.insert(playerData.Placed["itemPositions:"], {v.Name, v.PrimaryPart.Position.x,v.PrimaryPart.Position.y, v.PrimaryPart.Position.z})
		print(JSON:JSONEncode(playerData))
		Data:SetAsync(plr.UserId, playerData)
		end
	end
end)