You're missing 1 display option for 9!

[tastewar]

Your display options for 9 are missing one possibility: 5+2+1+1 :-)
I believe it should look like this in your code:

case 9:
  switch(random(3))
  {
    case 0:
      bits[0]|=offset;
      bits[3]|=offset;
      bits[4]|=offset;
      break;
    case 1:
      bits[1]|=offset;
      bits[3]|=offset;
      bits[4]|=offset;
      break;
    case 2:
      bits[0]|=offset;
      bits[1]|=offset;
      bits[2]|=offset;
      bits[4]|=offset;
      break;
  }