How to make roblox wait for local player?

So I have a script that works fine while It's in the players startergui, it creates a giant laser that moves around and kills anyone it touches, the problem is I want it to start off in the workspace and then be moved into the local players startergui. For some reason, while it's not already in startergui, I get an error that says "Workspace.Script:3: attempt to index local 'player' (a nil value)". I think it's because Roblox hasn't loaded the local player yet. Can someone Please tell me how to fix this issue!?

Script:

-- Get the player, character, and the players gui
local player = game.Players.LocalPlayer
local char = player.CharacterAdded:wait()
local hum = char:WaitForChild("Humanoid")
local gui = player:WaitForChild("PlayerGui")

-- Delay
    wait(1)

-- Parent the script to StarterGui and set the properties of wall
    script.Parent = gui
    wall = Instance.new("Part")
    wall.Name = "wall"
    wall.Shape = "Cylinder"
    wall.Rotation = Vector3.new(0, 0, -90)
    wall.Anchored = true
    wall.Size = Vector3.new(400, 8, 8)
    wall.Transparency = 0.7
    wall.Color = Color3.new(255, 0, 0)
    wall.CanCollide = false
    wall.Material = "Neon"

    wall.CFrame = char.Torso.CFrame + char.Torso.CFrame.lookVector * 5  
    wall.CFrame = wall.CFrame * CFrame.Angles(0, 0, 1/2 * math.pi)  
    wall.Parent = game.Workspace

-- Move the wall
    for i=1, 500 do

        -- If the wall hits someone, kill them
        function hited(hit)
            local hum = hit.Parent:FindFirstChild("Humanoid")
                if hum then
                    hum.Health = 0
                end
            end

        wall.Touched:connect(hited)
        -- Set the walls position
        wait()
        wall.CFrame = wall.CFrame + char.Torso.CFrame.lookVector * 5 + Vector3.new(0, 0, -1)        

        -- Destroy the wall eventually
        if i >= 500 then        
            wall:destroy()
        end

        -- If you get killed by the wall, it removes itself
        if hum.Health == 0 then
            wall:destroy()
        end
    end