Button not defined, why?

[Windspar]

@Johnny
1. Don't use python keywords as variables.

list = ['btn1', 'btn2', etc]

2. You can't use string as variables and making variables in functions are local only.
You have to pass them to other functions.
Something like this. buttons[0] - buttons[8]

def button_creation():
    buttons = []
    # other code
    for n in xrange(9):
        #new button
        buttons.append(Button(etc))
        buttons[-1].grid(etc)
    return buttons

@Barrowman
3.

# this get replace by next line
myname = "button" + txt # string
mayname = Button(etc) # delete string and now a tk.Button