Im no expert on drivers rules but I dont think anyone is actually right or wrong.
As long as his driver hours and WTD arent being compromised due to the earlier start then hes fine to do it after 9 hours off.
Although if I were the one paying the wages id also be pretty miffed at only taking 9 off so he can sit for 3 hours doing nothing (probably going back to sleep) yet still getting paid.
On balance though, I get the impression your colleague is a bit of a ■■■■.