I disagree that TBs don’t lose their baby brain, there are far too many saintly TBs who happily cart around true amateurs and kids.
The fact that they are a hot-blooded breed, bred for being more alert and sometimes more reactive, isn’t a baby brain thing, it’s a breed thing, and even that doesn’t apply to all of them.
My TBs “grew up” around age 9, but things started getting exponentially better around age 6 or 7.
Yes, deal with the horse you have that day.
He’s only been on a “real horse” program for 9-ish months. He’s still reconfiguring his muscles from track life, to bendy turny gather myself up, mentally as well as physically. He’s going to have moments of reverting back to 3-4 years’ worth of habits
Can your current trainer put a solid ride on him once a week? She might be better at feeling when he’s about to Baby Brain things, and redirect him before he can practice that old behavior
If you’re doing poles/jumps on straight lines, start putting them on circles - it will help everything about his unwanted behaviors because he will have to think a little harder about not tripping over poles, raised or not
Get the book 101 Jumping Exercises for Horse and Rider, as there are a ton of prep work exercise that don’t actually involve a raised pole. The Klimke book Cavaletti is also a must-have as well, Both of those have a ton of exercises that force the horse to slow down and think, which is what these types of horses really need.
Yes, it does get better