A handicap about five is to be recommended (9)
I believe the answer is:
advisable
'to be recommended' is the definition.
('advisable' can be similar in meaning to 'recommended')
'a handicap about five' is the wordplay.
'handicap' becomes 'disable' ('disable' can be a synonym of 'handicap'**).
'about' is an insertion indicator.
'five' becomes 'v' (roman numeral).
'disable' enclosing 'v' is 'dvisable'.
'a'+'dvisable'='ADVISABLE'
'is' is the link.
(Other definitions for advisable that I've seen before include "Wise, recommended" , "Prudent - recommended" .)