No official port exists or is planned. The PSP was discontinued in 2014; its active development window closed long ago. Sony has not announced, hinted at, or licensed a PSP version of Ape Escape 2 (originally PS2, 2002).
Porting a PS2 game to PSP requires significant re-engineering (CPU, GPU, RAM, controls, media). With the platform dead, the ROI is nonexistent.
The PS2 Classic on PS4/PS5 is the best official experience.