$8.67 is the gap closed.  Some will sell at this point and take...

$8.67 is the gap closed.  Some will sell at this point and take profit.  But as far as I know this generally is not a resistance level.  Gaps are generally stated that they will always close, unless its a breakaway gap in an uptrend.  

As you say, if A2M shows bad news, this will likely ripple to others, and shorts will thrown down again.  I would expect the support line to break if this does happen tomorrow.

The uptrend is primarily based on Elliot wave theory .  A key factor here is that Wave C cannot retrace past Wave 4 (support line).  Technically it has by a couple of cents, but no idea if in reality that small amount kills the theory, I doubt it.  If this holds, then obviously no place to go but up... pretty simple!