Is the d-block ever part of the valence electrons?
The answer is merely a matter of definition of "valence electrons".

Many texts define "valence electrons" in a way that explicitly includes d electrons of unfilled (but not filled) d subshells. 

For example: Chemistry structure and dynamics by Spencer et al. at page 125:[1]


  We can define valence electrons as electrons on an atom that are not present in the previous rare gas, ignoring filled d or f subshells.


Many books published in the last 10 years use this definition. 

That d electrons may be valence electrons is also supported by the 18-Electron rule (at least to the extent that there is such a rule).  

[1] James N. Spencer, George M. Bodner, Lyman H. Rickard: Chemistry: Structure and Dynamics, 5th Edition. John Wiley &amp; Sons: 2010. ISBN: 978-0-470-58711-9