Found some new stuff, that should bring the run to sub 8 hours:

1. SSD - not sure how much faster the loading times will be, but even just one second per one race would make the run faster by at least 4-5 minutes.

2. Skip Rachel's tutorial speech - saves around 20 seconds.

3. Turn off "Crowds" - I found this by accident, but if you keep this setting turned off, you won't see those annoying cutscenes at the beginning of each race. Shouldn't save much as these can be skipped, but every second helps.

4. 6th gear, Differential and LSD skip - this is what online racers use, because you get much higher top speed. You also get slightly better launches, which combined with higher top speed results in much better drags. I was also surprised the car can do much better and longer drifts. My average scores went 15-30% higher and I've already managed to easily beat all stage 4 drifts without using GTI, so it's possible I won't need it at all, thus save 2-3 minutes. As for the races, I did quite an extensive testing and there doesn't seem to be any difference on twisted courses. There's however difference on highway courses.

We should try and make a no loads timer.

I forgot to mention I have found a way to completely workaround the event respawn RNG. Basically, everytime you load your career or profile a certain number of events are randomly spawned on the map from some kind of pool, so if you know the exact positions of all events, you can just keep reloading the game till you get it spawned. This usually happens on 1-3rd attempt and the reload trick itself takes about 6 seconds to do. This should easily save at least 15 minutes over my previous run as I can ignore most of the circuits.

It also means there is probably no way this game can be speedrun segmented, because the continuity can't be verified - you could simply use newly unlocked upgrades without anyone knowing about it. There's also not much point doing so, because it would be just a bit faster - maybe half an hour.