If a pet is stat capped, does that mean I can no longer use any type of booster? 😭

Correct. you also will not gain any EXP when battling with a capped pet (you can still obtain loot). However, you are easily able to leech your capped pet to bring them back to uncapped, and earn EXP/use boosters again if you leave them uncapped.

That's good to know! For example, I don't need a lot of level. If I reduce it enough, I can put that exp on another stat?

Level is not included in the stat cap nor is intelligence. It's only a combination of HPs/Str/Def/Spe that are in the stat cap calculation.

Does Barin need to be reduced anywhere? I wish I was able to get 11,000 health

Level: 4012 Health: 10488 / 10535 Strength: 9139 Defense: 7979 Speed: 7355 Intelligence: 6794

Up to you to decide where or how you wanna remove 465 points from the other 3 stats. Leeches are 1 medium token in the battle shop each and reduce a stat by 2 points when used.

You can still use intel boosters if your pet is capped, just to clarify.:)