Compiler error: "invalid octal digit". This happens for array [8] and [9]. Have changed array name but to no avail. Picture is attached. Help required

You cannot write the integer constant 8 in that way. You must remove the leading zero.
The C standard requires that any integer constant that starts with 0 and is not immediately followed by the character 'x' is an octal number, and the digits '8' and '9' are not valid octal characters.