Can someone make it so the player doesnt get unlimited points?

local enabled = true -- Debounce

script.Parent.Touched:connect(function(hit)
    if not enabled then return end -- Check for debounce
    enabled = false
    local player = game.Players:GetPlayerFromCharacter(hit.Parent)
            player.Backpack:WaitForChild("Hamburger") --[[

I suggest replacing the "WaitForChild" for "FindFirstChild", since the first will yield the function indefinitely if the player doesn't own a Hamburger.

]]-- 
    if hit.Parent:FindFirstChild("Humanoid") then        
            player.leaderstats.Candy.Value = player.leaderstats.Candy.Value + 100
            local hamburger = player.Backpack.Hamburger         
            script.Sound:Play()
            hamburger:Destroy()
            script.Parent:Destroy()
    wait(1) -- Change it to the amount of sec you wish to have as cooldown
    enabled = true
end
end)

Your script should be good to go, however I would suggest a couple modifications. As it is now, it will only give points to players who have their Hamburger tool Unequipped. Also the debounce will trigger regardless of the player actually owning a Hamburger or not (thus disabling the button for everyone for the given cooldown). Here is the script adapted to my suggested modifications:

local enabled = true -- Debounce

script.Parent.Touched:connect(function(hit)
    if not enabled then return end -- Check for debounce
    local player = game.Players:GetPlayerFromCharacter(hit.Parent)

    if player.Backpack:FindFirstChild("Hamburger") or hit.Parent:FindFirstChild("Hamburger") then -- Check for hamburger

        if not hit.Parent:FindFirstChild("Humanoid") then return end -- Check for humanoid
        enabled = false
        player.leaderstats.Candy.Value = player.leaderstats.Candy.Value + 100
        local hamburger = player.Backpack.Hamburger         
        script.Sound:Play()
        hamburger:Destroy()
        script.Parent:Destroy()
        wait(1) -- Change it to the amount of sec you wish to have as cooldown
        enabled = true
    end
end)

Infinite yield possible is put in the output when :WaitForChild() has waited a long time. It means that the instance that it is waiting for might never come. If it does eventually arrive, then the script will go on as normal.

local debounce = false

script.Parent.Touched:Connect(function(hit)
    if debounce then return end
    local player = game.Players:GetPlayerFromCharacter(hit.Parent)
    if not player then return end
    local h = player:WaitForChild("Backpack"):WaitForChild("Hamburger")
    local l = player:WaitForChild("leaderstats"):WaitForChild("Candy")
    debounce = true
    l.Value = l.Value + 100
    script.Sound:Play()
    hamburger:Destroy()
    script.Parent:Destroy() -- We dont need to put "debounce = false" since the button and script are both gone.
end)