I'm in Florida, Sarasota area. Can a Pachira be planted in the ground here? I have one growing in a pot and has gotten very large. I never see it discussed except as a house plant.
Your zone seems to border 9b/10a so some might consider it 'zone pushing' as they are rated zone 10a. (But heck, I am growing palms and subtropical fruits in the North, so not objective here.)
If you have a site near the house with protected exposure, I bet it would work out for you. Good luck.
I have a good sized tree growing in zone 10 that got hurt badly by the cold a few years back. It bounced back so quickly I hadn't even trimed the damage as it was still winter. So in your area it may get hurt in the winter but I bet it comes back better than ever. This year I have so much fruit on the tree its unbelievable. The nuts are wonderful if you let them sit long enough.