Additional tracks and characters can be added to the Switch version via the Booster Course Pass DLC PSP Alternatives & Homebrew Homebrew Projects:
Mario Kart 8 Deluxe is an exclusive title for the Nintendo Switch does not have an official release or download for the PlayStation Portable (PSP) mario kart 8 deluxe psp download
There have been historical fan-made "homebrew" projects, such as the mario-kart-psp project hosted on Google Code Archive Additional tracks and characters can be added to