the reason so many recommend a 9 speed freehub over a 9 speed freewheel is because on the freewheel hub the cones are much closer together than they are on a freehub and that closeness means that there is a pretty long length of unsuported axle on the freewheel hub. That's what causes the bending/breaking of the axle. You're almost guarranted to bend/break a 9 speed freewheel hub axle. the freehub axle is very much stronger.

If you do spread your dropouts to 135mm be sure to get them realligned so that you don't break one in use.

Cheers