Why does this not put the wand in my backpack?

The Touch Parameter returns your the object that triggered the event to access the Player you'll need to use GetPlayerFromCharacter()

local part = script.Parent

function onTouch(player) 
local wand = game.ReplicatedStorage.Tool:Clone()
local Player = game.Players:GetPlayerFromCharacter(player.Parent)--Getting the Player using the Character.
if Player then--This prevent errors from occurring, like for example if your function was triggered by an object it won't have a Backpack would it?
wand.Parent = Player.Backpack
	end
end


script.Parent.Touched:connect(onTouch)

~UserOnly16Charcters, Hoped I helped you to answer your question! If you have any further question, don't hesitate to comment below!!