Decision Tree: Tic Tac Toe

In classic TicTacToe, assuming that O moves first:
There are theoretically 9 possible first moves.
However, by rotating the board, you can discover that all corners are the same, and all edges are the same.

CORNER
 O  .  . 
 .  .  . 
 .  .  . 

CENTER
 .  .  . 
 .  O  . 
 .  .  . 

EDGE
 .  O  . 
 .  .  . 
 .  .  . 

To simplify the matter, we will assume that O always goes first, and always goes in the middle.  This means that X turn 1 is either a corner or an edge, by rotation, only two possibilities.  
					  CENTER
					 .  .  . 
					 .  O  . 
					 .  .  . 

CORNER
 X  .  . 
 .  O  . 
 .  .  . 
EDGE
 .  X  . 
 .  O  . 
 .  .  . 

On O next turn, if X moves in the corner, X move can be classified as:
adjacent edge, opposite edge, adjacent corner, opposite corner.
(Might need to do a mirror image to see that of the 7 positions, three of them are mirror image pairs.)
O next turn, if X moved on the edge, can be classified as:
adjacent corner, adjacent edge, opposite corner, opposite edge, again 3 mirror pairs.

X moves:
				CORNER							  EDGE
				 X  .  . 							 .  X  . 
				 .  O  . 							 .  O  . 
				 .  .  .							 .  .  . 
O moves:

CORNER1
 X  .  . 
 O  O  . 
 .  .  . 

CORNER2
 X  .  . 
 .  O  O
 .  .  . 

CORNER3
 X  .  . 
 .  O  . 
 O  .  . 

CORNER4
 X  .  . 
 .  O  . 
 .  .  O 

EDGE1
 O  X  . 
 .  O  . 
 .  .  . 

EDGE2
 .  X  . 
 O  O  . 
 .  .  . 

EDGE3
 .  X  . 
 .  O  . 
 O  .  . 

EDGE4
 .  X  . 
 .  O  . 
 .  O  . 

 								Example						
seth		Bailey		Logan						Gabe					
Kyle		Linden		Colin						Myles		John		
		
For 6 of these 8 situations, if X does not immediately block, O will win on Os next turn.
For your assigned situation: 
	generate all possible X moves (6)
	for each of those X moves, generate all possible O responses (5).
	
For each set of O responses to each X response, identify which response is LEAST valuable to O.  Mark that as the likely X move. If you see any that do not need to be considered, further, mark them. 
For each O response, consider the designated X response.  Which of them is MOST valuable to O?
Recommend that move for O.

EXAMPLE:							 X  .  . 
CORNER4							 .  O  . 
(Three unique moves possible for X)			 .  .  O

CORNER4 A							 X  .  . 
								 X  O  . 
								 .  .  O
Possible O responses to CORNER4 A:

CORNER4 A1
 X  .  . 
 X  O  . 
 O  .  O

CORNER4 A2
 X  .  . 
 X  O  . 
 .  O  O

CORNER4 A3
 X  O  . 
 X  O  . 
 .  .  O

CORNER4 A4
 X  .  O 
 X  O  . 
 .  .  O

CORNER4 A5
 X  .  . 
 X  O  O
 .  .  O

O:2 ways to win     O: 2ways to win    O: 1 way to win      O:1 way to win   O 1 way to win
Obviously, O would choose A1 or A2, and win. So X would NOT choose corner4 A.

CORNER4 B							 X  .  . 
								 .  O  . 
								 X  .  O

Possible O responses to CORNER4 B:

CORNER4 B1
 X  .  . 
 O  O  X 
 X  .  O

CORNER4 B2
 X  O  . 
 .  O  X 
 X  .  O

CORNER4 B3
 X  .  . 
 .  O  X 
 X  O  O

CORNER4 B4
 X  .  O
 .  O  X 
 X  .  O

CORNER4 B5
 X  .  . 
 .  O  X 
 X  .  O

O would like CORNER4 B2 or CORNER4 B3, but not certain to win with either
X would prefer CORNER4B to CORNER4A.

CORNER4 C							 X  .  . 
								 .  O  . 
								 .  X  O
Possible O responses to CORNER4 C:

CORNER4 C1
 X  .  . 
 O  O  . 
 .  X  O
CORNER4 C2
 X  .  . 
 .  O  . 
 O  X  O
CORNER4 C3
 X  O  . 
 .  O  . 
 .  X  O
CORNER4 C4
 X  .  O 
 .  O  . 
 .  X  O
CORNER4 C5
 X  .  . 
 .  O  O
 .  X  O

O would like CORNER4 C1, C2, C4,C5, but not certain to win with any.
X would prefer CORNER4C to CORNER4A.