Chocobo Training (help)

The best stats, in order of importance are:
1. Max speed
2. Stamina
3. Endurance
4. Cunning
5. Acceleration

If you only race on Sagolli Road, you can pretty much ignore Cunning because there isn't very much terrain where Cunning is useful. Really you shouldn't train Cunning or Acceleration at all because the points are better spent on Max Speed and Stamina, with a few left for Endurance before you hit rank 50. It's also possible to win races right up to pedigree 9 without doing (much) training so if you're aiming for a P9 you may as well not spend the MGP; you only really need exp until P9 when it's hardcore training time. Chocobo Challenge is the best way to make a big chunk of MGP fast (I think?) as completing all 15 challenges earns 445,000MGP. To beat the final challenge you pretty much need a P9 with perfect stats; I managed it with everything perfect except for 3 stars in cunning. For training, I maxed out Max Speed first, then Stamina, then spent everything remaining on Endurance. I didn't touch the other two stats.
https://imgur.com/a/95wEwZF

There's a little bit of RNG when it comes to consistent winning because of items, but generally you need to try and find the right balance so you run out of stamina right at the end of the course.

Looking at your chocobo's stats, you're in a pretty good spot for breeding because you've got the most important stat (Max Speed) maxed out in both parent slots. It took me ages to get my almost-perfect P9 (max in everything but cunning but I only race Sagolli Road so it doesn't matter anyway) because I had a 50/50 chance of getting 4 stars or 1, so I had to keep rolling the dice.
Are you familiar with how parentage and breeding works? At P6 it's going to be getting important pretty soon.