Information hiding up in caves a bat adopted (8)
I believe the answer is:
database
'information' is the definition.
(database is a kind of information)
'hiding up in caves a bat adopted' is the wordplay.
'up' is a reversal indicator (in down clue: letters go upwards).
'hiding' says the answer is hidden in the clue.
'esabatad' is hidden in the letters of 'in caves a bat adopted'.
'esabatad' backwards is 'DATABASE'.
(Other definitions for database that I've seen before include "computer store" , "Where figures might be" , "Lots of info" , "whole lot of information is needed" , "information held by PC" .)