Would you believe I found William spelled this many ways in the 1865 census? vilem, vilham, vilhelm, vilhjem, vilhlem, vilhlm, vilhm, vilhælm, viliam, viljam, viljen, villam, villeam, villeim, villem, villeum, villiam, villium, villjam, villom, villum, vilom, vilum, wileam, wilehem, wilem, wilh, wilham, wilhan, wilhelem, wilhelm, wilhelmn, wilhem, wilhilm. Those names, born 1855-56-57 give 176 possibilities spread in ALL provinces.
Colson is quite impossible. (At least for me, guessing at possibilities.)
I think you will have to find some more facts. The most useful would be his father's first name. Birth place or region, port of emigration?
Have you, by the way, looked on familysearch.org? Their searches are good at guessing at alternate spellings.
What did he name his sons and what were his brothers' names? That might be a hint as to his father's name.
The good news is that the 1865 census is very nearly complete, and a 9-year-old should be living with his parents. Find some more info and we'll find him.