I think you'll have better success by looking for each person. Ernest & Annaie's obituaries will tell you where the children were living when their parents died.
1920 Centertown, OHio, KY
Ernest Msartin, b. KY, 22, loader coal mine
Annie, b. KY, 22
Male Infant Martin
Born & Died: March 31, 1921, Crestan Town, OHio, KY
COD: premature birth
F: Ernest Mratin, b. KY
M: Anna May Phelps, b. KY
Informant: Ernest Martin, Center Town
Buried: Centertown Cemetery, 4/1/1921
Source: KY Death Records 1911-1963
1930 Rockport, Ohio, KY
Ernest Martin, b. KY, 31, laboerer coal mine
Anna, b. KY, 31
Marvin, b. KY, 7
Harold, b. KY, 5
Irene, b. KY, 3
Edward, b. KY, 9/12ths
1940 Ohio Co. KY
Earnist Martin, b. KY, 42, education=high school 2 yrs
Annie, b. KY, 43, educ=7th grade
Marvin, b. KY, 17
Harold, b. KY, 16
Irine , b. KY, 13
Edward, b. KY,. 11
Allice, b. KY, 1
I didn't find Earnest and Annie's death info.
You can contact the Ohio County Public Library Annex, www.ohiocountypublic
library.org/genealogy.html and ask if they have a local death index.
The Ohio County Historical Society, www.ochistoricalsociety.org/?page+id=85
may have info about the family. Successful SEarching!