Well.. it's untested but, you CAN manually toggle 8 directional sprites on or off at any time( you will need to change the sprite of the character to match the format though at the same time ), with the following script call..
// for the player. $gamePlayer._8dirSprite = true; // for events. $gameMap.event( ID )._8dirSprite = true;
The above will turn ON 8 directional sprites, if you set the value to false it will turn them off instead. and replace "ID" with the actual ID of targetted event.
Lastly do not forget to change the sprites! otherwise you will get some... graphical issues :x