"professor" comes to mind as a 9 letter word
You could use ascertain or determine instead of gaining knowledge. If you want synonyms for learning, you could use education or schooling.
Learning
The nine letter word is tolerable.
wot is a nine letter word for a alian
The nine letter word is nectarine.
Waterhose is a nine letter word starting with the letter W!
The nine letter word is overdraft.
Economics
A nine letter word for wooing might be romancing.
Algorithm is the only nine letter word.
There is no nine letter word that can be spelled with the letters 'aelccdnst'.
What is a nine letter word meaning very tidy
a nine