In a linear time invariant system, is it possible for a SS response to exist, when we have a bounded input?
I don't do z-transforms in my sleep, but if I read the next two bullet points in the text you referred to, they say


  
  If the input signal has a pole on the unit circle then there is a persistent sinusoidal component of the input signal. The forced response to such a sinusoid is also a persistent sinusoid
  In this case, the forced response is also called the steady-state response.
  


From this I can deduce that 


An input with a pole on the unit circle is also a bounded input in the time domain (because the sinusoids are bounded functions). So it's not correct that all poles must be within the unit circle for the input to be bounded.
The text defines the steady state response as the response to an input with a pole on the unit circle, not the response to an input with all poles within the unit circle. That is, it defines the steady state response as the response to an input with a sinusoidal component, not the response to an input that decays as \$t\to\infty\$.