You need to give more ages and places - there were a lot of William Kermeens.

Is this your family in the 1881 census?
William KERMEEN Head M Male 36 [born] Isle of Man, Joiner
Elizabeth KERMEEN Wife M Female 37 [born] Wesbury, Shropshire, England
William KERMEEN Son Male 10 Waterloo, Lancashire, England Scholar
Elizabeth Ann KERMEEN Daur Female 8 Waterloo, Lancashire, England Scholar
Maggie KERMEEN Daur Female 6 Waterloo, Lancashire, England Scholar
Emma KERMEEN Daur Female 4 Waterloo, Lancashire, England Scholar
Walter KERMEEN Son Male 7 m Waterloo, Lancashire, England
John EVANS Bro In Law U Male 20 Wesbury, Shropshire, England Joiner
Harriet TASKER Serv U Female 15 Lpool, Lancashire, England Genl Serv
Harriet EVANS Visitor U Female 20 Wesbury, Shropshire, England
George M. SMITH Lodger U Male 20 Barmby Moor, York, England Iron Mongers Assistant.
Source Information:
Dwelling 34 Albert Rd
Census Place Great Crosby, Lancashire, England
Family History Library Film 1341885
Public Records Office Reference RG11
Piece / Folio 3695 / 53
Page Number 27

If so, and if his age is accurate in the census, William b.IOM could have been bapt 8 DEC 1844 Patrick, Isle Of Man, Father: WILLIAM KERMEEN, Mother: ANN KNEALE. [IGI]
Both records are from FamilySearch.org

There was another William Kermeen b.1842 in Lonan, and another b.1848 in Maughold.

Sue