I doubt it would work because of the 6 amp rating vs. your 9 amp rating. Have you looked online for "Osco door opener parts"? I looked with that search, and found several sites, but without a model number for your opener, could not get you any help. The website below might help you:

https://www.proteccontrols.com/pages/linear-osco-operator-replacement-parts

If not, try one of the other sites from the Google search.  If you have an electric shop near you, that does motor rewinds, they usually have catalogs for small motors and might be able to match yours.  Grainger is another source for small electric motors, where you can see several at once with their particular specs.