They are going to pressure him to get the biggest possible deal. If you don't think this, you aren't familiar with Donald Fehr and how unions work in general in sports. McDavid's deal is a chance to set a new benchmark for the highest paid player, there is absolutely pressure from fellow agents, players and unions to maximize his earnings. This was post-Fehr, but a well-known tactic. Here is LaRussa talking about it in regards to Albert Pujols.
http://www.tampabay.com/sports/la-russa-claims-union-is-pressuring-pujols/1151878
Baseball operates much differently though. I get your point that Fehr's background resides there, but it doesn't change the fact that the money/TV contracts/gate revenues are all very different, not to mention the culture of the athletes (sorry, but there are way more divas in baseball - I'm looking at you Jose "I want 6 years, 150 mil despite my declining performance" Bautista).
Crosby took 8.7 per over 12 years, basically conceding any chance to ever be a UFA. Was there different circumstances? Sure, his concussion issue was still a bit worrisome, and the contract structure was different because there weren't limitations to term yet. The cap was close to the same (69 mil when it kicked in, not much different from current figures). But he was also a cup winner and, despite the concussion, still the best player in the world (at worst, top 3).
I'm shocked that so many people consider the 8 year, 9.7 per suggestion to be some slap in the face. McDavid would still have the potential to be a UFA at age 29, he would only give up 4
UFA years, and he'd still be in the top 5 salaries in the game directly out of his ELC. It is very fair for both parties. This is aside from the fact his personality really suggests that he would be the type to leave a bit on the table if it can make the team better (see his friends Stamkos and Tavares).
If he tears the league a new one and finishes 30 points ahead of everyone, maybe we can revisit these max contract suggestions, but to be paid top 5 in the league coming out of your ELC (which 9.7 would be) is well within reason for McDavid.