Can I get the rewards for the level i am at tomorrow or it's now or never?

Usually we can still claim rewards for 24 hrs after the end of an event, but I don't really know if that will apply to Battle Pass.

unclaimed rewards are automaticly claimed when battle pas isn't available anymore is what i have heard. x2 XP is deleverd into inbox. Other items directly to your accaunt. Energy refill automaticly used.

I don't know if when you have gold pass the xp and silver boots is active till season 2 starts or till season 1 ends.