No, RAW are the rules as written in books and the errata only
Crawford makes rulings, not rules1
Jeremy Crawford makes rulings on Sage Advice and Twitter. He does not make rules there.
Official rulings on how to interpret unclear rules are made in Sage Advice.
The "rules" here are RAW and rulings are interpretations of those rules. Crawford is not at any point (or at least shouldn't be) creating a new RAW. Instead he is giving us his ruling (his interpretation) of the rules (as written in the books). By definition a ruling is not a rule, so Crawford's rulings cannot be a Rule as Written. So, whether via Twitter or Sage Advice, or Acquisitions, Inc., his rulings are not considered to be RAW.
Crawford has even agreed with this view on the matter (albeit indirectly) in this Tweet:
Q: Does something become RAW simply because you say it on Twitter, or is RAW only what's actually in the books?
JC: Official rules are in rulebooks. On Twitter and in Sage Advice, I give rulings and clarifications. The DM decides what to do with them.
In other words, he is saying that, no, his Tweets and other rulings are not Rules as Written -- they are rulings. The rules you find in the book and the ruling he is making is interpreting those rules.
His rulings are often a good yardstick for judging how the designers intended the rules to work though ("Rules as Intended" or RAI). From the Adventurers League FAQ:
Sage Advice is a great barometer for ‘rules-as-intended’
In fact, anything he does on Acquisitions Inc. is probably not even considered Sage Advice:
One exception: the game’s lead rules developer, Jeremy Crawford (@JeremyECrawford on Twitter), can make official rulings and does so in [the Sage Advice Compendium] and on Twitter
Since Acquisitions Inc. is neither of the two sources, they probably aren't even considered to be rulings in the way other Sage Advice ruling are.2
So, nothing outside of the books and errata is considered to be RAW and Jeremy Crawford's rulings are not "Rules Canon" (RAW) for anything.
His DMing is going to focus on intent and fun, not RAW
In an interview about him taking over Acquisitions, Inc. Jeremy Crawford says much the same thing:
One of the things in our early discussions with Penny Arcade that we talked about, that would be fun about me taking the DM’s seat, is that it would be a chance for me as lead rules designer to actually show how many of these rules can be used, and honestly how they’re intended to be used. Now ultimately my intent doesn’t matter; what really matters is what each DM wants, but it is a chance for me to show off some of the tools we’ve provided so that DMs can see there are all sorts of ways [in the rules] for people to have a fun time and not worry about minutiae. Because we put some of these things in the game precisely to make people’s life more easy and more fun.
Jeremy Crawford will be taking this opportunity to show off the rules and how they can be used to enhance fun at the table, but he makes it clear that he wants to show off the intent of the rules. Additionally, I don't think from his above statements that sticking to or making RAW rulings is going to be a priority at his table. It will certainly be interesting to see how he rules, but it is nothing that any other DM has to worry about.
1 - Outside of him writing rules in the books in his capacity of Lead Rules Developer for D&D 5e of course.
2 - Thanks @NautArch