It turns out there is a much easier variation of Ico's starting strat! Now I don't know if it's actually faster or not, but it's good enough at least. The real reason I even could get the world record is because of my ending, where you just zoom all the way to the finish. This route honestly makes the level quite comfortable now and very straightforward. I'd imagine this route can at least get sub 9s with a perfect run, but after that it'd be tough to improve by much more.