Hello,

You could see how the igMaskEditor could be setup using the includeKeys option:
“Sets gets ability to enter only specific characters in input-field from keyboard and on paste.
Notes:
If "excludeKeys" option contains same characters as this option, then "excludeKeys" has priority.
Letters should be set in upper case.
Making difference between upper and lower case is not supported.
Note! This option can not be se runtime.”

I have created a sample for you at: http://jsfiddle.net/sc6qjoro/1/
You may also want to adjust the inputMask and dataMode options to better suit your requirements.

For example, the inputMask could additionally expect digit characters:
9: digit character. Entry is optional.
0: digit character. Entry is required.

In the context of igGrid, the settings will be included under features and could be as follows: 

features: [
            {
                name: "Updating",
                editMode: "row",
                responseDataKey: "results",
                columnSettings: [
                    { columnKey: "lastName", readOnly: true },
                    { columnKey: "firstName", readOnly: true },
                    { columnKey: "score", editorType: "mask", required: true, dataMode: "int",

                        editorOptions: {
                            inputMask: "0", dataMode: "rawText", includeKeys: "1"

                        }
                    },
                ], 

Please let me know in case you need further assistance!