I currently am getting no sound of passengers boarding or unboarding. Had that fairly nicely in the old version.
That's because you have updated using the GSX Vehicles updates, and in the few hours after release, those installed didn't contained all the updated sounds. This is fixed now, so either download the vehicle updates again, or just use the full installer.
The marshaller, when he approaches any airplane the first thing he says is "locking gear" and at that point nothing else until he goes into the by pass pin inserted speech etc.. Seems like something is missing. He says the other stuff a few seconds later. Same after the push back. He says "locking gear" and a few seconds later pins removed. Seems like it should be something else besides just locking gear being said. Just sounds like something is missing. This was true with the older version as well.
I don't see a problem here. He's not supposed to say anything after "locking gear", you should hear a mechanical or pneumatical sound (depending on the pushback type) and the marshaller will perform an animation of moving the handle (except for the towbarless models) and then he'll walks away and will say that pushback pin has been inserted and you should release brakes.
That's how it always worked, and I don't see a problem with it.
With this new version 1.9 there seems to be a LOT of vehicle crashes. When boarding, the baggage train comes up and parks and then the container train comes up and goes right through it. When the baggage train leaves it does several tight circles, crashes into itself several times then leaves. The container train does the same when it pulls away. It does a tight circle, runs over it's own trailers, then goes away. It did this in the older version but I don't believe as blatant as this is doing.
Not a single bit of these has changed with the new version. If you said you saw conflicts between the previous vehicles and the deicers going away, I might agree, but the other vehicles behave as they always had.
The only possible solution to reduce clashes between vehicles, is to tweak their starting positions with the parking customization editor. Vehicle are not entirely aware of each other, because that would cause even more problems that it would fix (possible deadlock), so we only have timings to play with, and you have starting positions you can tweak, to minimize the issue, since GSX can't anticipate any arbitrary scenery configuration.
All else seems well. The catering truck seems fine. Doesn't line up perfectly but is fine.
The catering vehicle lines up as accurately as the service door position is accurately set in the airplane configuration file. So, if you have this issue in an unsupported airplane you customized yourself, try to be more precise. If, instead, you are getting less than perfect alignment with an internally supported airplane, you can easily refine it with the airplane configuration utility and, if the problem look too obvious, please report which airplane is, and if you are using the internally-supplied config that comes with GSX, so we can check it.
As to the boarding sounds though, in the older version previous to 1.9 I had nice foot steps it seemed. I thought I heard chatter but wasn't sure. But with this one I hear nothing and the volume is all the way up.
What do you mean "nothing" ? You mean you don't have the foot steps sound anymore, or no boarding sound at all ?