I got a response from DNR, Sunday hunting for resident geese is not allowed.
Thank you for contacting the Maryland Department of Natural Resources.
Maryland's resident population of Canada geese are managed under the authority of the Migratory Game Bird Treaty Act https://www.fws.gov/birds/policies-and-regulations/laws-legislations/migratory-bird-treaty-act.php . This federal legislation, enacted in 1918, governs the management of all migratory bird species including Canada geese. This means that even though resident geese nest, and spend most of their lives in Maryland, they are legally designated as migratory game birds.
As you noted, the Maryland Guide to Hunting and Trapping Regulations mentions explicitly that http://www.eregulations.com/maryland/hunting/migratory-game-bird-hunting/ migratory game birds may NOT be hunted on Sundays (please see the first bullet) and this is true for resident Canada geese as well.
Thank you for your question and good hunting!