One who’ll go far perhaps rebuked about line supporting rash study misguidedly (9,5)

I believe the answer is:
thursdays child
'one who'll go far perhaps rebuked' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'line supporting rash study misguidedly' is the wordplay.
'line' becomes 'child' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'supporting' means one lot of letters go next to another (in a down clue, some letters go below others).
'misguidedly' indicates an anagram.
'rash'+'study'='rashstudy'
'rashstudy' with letters rearranged gives 'thursdays'.
'child' after 'thursdays' is 'THURSDAYS CHILD'.
'about' acts as a link.
Can you help me to learn more?
