It`s a great thing you offered that tidbit cuz he would have never thought of it. 
I actually thought of the same thing when I was watching the video. I have a toddler kids bench I never put together I just finished putting it together and I think it may be too small.
I would like him to be able to rack and unrack the weight himself may need to look for a kid bench online
Maybe a standard old school style bench vs a wider olympic and bar will fit
The bar is too short to rack on my bench but he also has short arms so need it not as wide and lower
They make crappy toddler benches which I have but no real kid size quality bench