I think that is highly possible that it is the same Marcellus KERCHEVAL.
During my quest for information on the KERCHEVAL family I only found one Marcelus and have the following notes in addition the listing in the 1860 census:
In 1870 there is a Marcellus KERCHAVAL, age 15, in Berryville, Clarke Co, Virginia. He is living with James and Emma (Kercheval) HOWELL. This HOWELL line is the one I was tracking for my sister-in law.
The census index for 1880 lists him as Marcel KERCHEVAL in the West Charleston District of Jefferson Co., W VA. He is a boarder in the George KEENE household, age 24 and single, occupation Printer. He and his parents all born in VA .
I was not sure whether I had found Marcellus in the census for 1900 until your posting. The household I noted was found in 1900 in Jefferson Co. West Virginia. (no name or age easily decipherable for the head of household, nor age of spouse)
KERCHEVAL, (Mxxclus?) - HH,w,m,b:Oct 1855,married 18yrs KERCHEVAL, Sarah - wife,w,f,b:Sep 1854,married 18yrs,Ch:3/1 KERCHEVAL, Mary E - dau,w,f,b:Mar 1885, age 15
Head of household b:VA his father in PA, mother in VA Wife, Sarah b:W VA her father in RI and mother in W VA
In 1910 Marcellus was again found in Jefferson Co., W VA (this time as Marseller D Kercheval age 55) Living with him were his wife Sarah E.,age 57 and daughter Mary E., age 24, who is single and a "teacher in the public schools"
In 1920 Mary E. is listed as ‘Elizabeth” age 34 still unmarried, Teaching in the Graded School and living with her widowed mother in Jefferson Co., W VA. It appears her mother died prior to the 1830 census, though I do not know the date.