This is just a guess: It is some time since I bought Alden shoes ( mine were direct purchases and not vintage ). But I remember that there were two "sizes" that Alden used: The standard size, like 10-1/2 in the shoe shown in your link, and the heel size, which may be the 9F on that shoe, although I am not sure how that number or letter would be arrived at.
In my own shoes from a decade ago, the two sizes, which are specified because Alden uses split lasts, are shown with letters above and below. So 10 C/D might be a 10 D shoe with C indicating heel width. Obviously your shoe, which is somewhat older, may have a different scheme. The other numbers may be related to production years and months and similar codes.
Here is some information on current Alden practices: