Pig-headed old boy at home in Texas perhaps (9)
I believe the answer is:
obstinate
'pig-headed' is the definition.
(I've seen this before)
'old boy at home in texas perhaps' is the wordplay.
'old boy' becomes 'ob'.
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
'in' is an insertion indicator.
'texas perhaps' becomes 'state' (texas is a kind of state).
'in' inserted into 'state' is 'stinate'.
'ob'+'stinate'='OBSTINATE'
(Other definitions for obstinate that I've seen before include "Stubborn, obdurate" , "Like mules" , "Stubbornly persistent" , "Mulish" , "Pig-headed" .)