Change into home gear first to get disguised (9)
I believe the answer is:
incognito
'disguised' is the definition.
(I've seen this in another clue)
'change into home gear first' is the wordplay.
'change' indicates an anagram.
'home' becomes 'in' ('he's home' can mean 'he's in').
'gear' becomes 'cog' (I can't explain this - if you can you should believe this answer much more).
'first' is a charade indicator (letters next to each other).
'into' is an anagram of 'nito'.
'in'+'cog'='incog'
'nito' put after 'incog' is 'INCOGNITO'.
'to get' is the link.
Can you help me to learn more?
(Other definitions for incognito that I've seen before include "With true identity concealed" , "under another name" , "Under assumed identity" , "In disguise" , "as disguised person appears?" .)