Because i have been a good boy this year, Santa’s brought me a dropper seatpost . Its return is set by air pressure from a shock pump? so 2 questions .
1, will it be ready to go (with air pressure in the thing)
2, whats the difference between a shock pump and a tyre pump(is it higher pressure)
thanks in advance

1 maybe..
2 Tyre pump=high volume low pressure
Shock pump=low volume high pressure

It should come with air in it.

You are unlikely to achieve 250psi with a track pump!