If they re-use tracks from mario kart 8 deluxe, which they might do, it may be a good move to allow crossplay on these for mario kart 8 players with mario kart 9.
Then again, i laugh at leaks saying "they'll announce a new mario kart, a new mario, a new pokémon, a new zelda"... Yeah... I can announce a new year for next year too, it wouldn't be less stupid.
A rumor is saying that all the games that pokemon company talks about on pokemon day will be for switch 1 only, meaning pokemon legends ZA is a switch 1 game only. They may keep the big reveals for the 30th anniversary on 2026. Well, switch didn't have any pokemon game except let's go for like 2 years.