Definitely read the links Melbrod shared!
Some puppies are more reactive, nervous, and/or unsure than others. At 9-weeks old she is still very young and you've got a lot of time before I would consider it to be a true red flag or major concern.
Briefly, what I do with puppies (and even dogs) who are reactive and nervous is I just take them somewhere people frequent - maybe a city park or a shopping center or a grocery store or a university campus (obviously, it might be a little more challenging to find a location) - and I take some super tasty treats and we just people watch from a distance. I try to sit somewhere with the pup that it's unlikely we'll encounter people directly. I don't want strangers approaching a puppy who is freaked out by people.
And basically I just offer praise and treats for the puppy observing the environment. If your puppy won't take treats, that's okay, but you might move a bit further back again. (An inability to take treats or play with toys can be a sign of stress or conflict about a situation.)
You'll have to figure out how far away you need to be to prevent her from reacting. The idea is to sit just outside of what she perceives to be "the danger zone" and watch people and reward her for not freaking out. If she's handling that well, then maybe you can move in just a bit closer, and continue to do that to help desensitize her to their presence. If at any point she gets upset about people, move back farther again.
Also, I let the puppy decide if they want to meet someone. With reactive puppies, I *never* force them to meet someone. They have to show interest before I approve the interaction. Even if they seem neutral, they might just be comfortable (finally) with someone strange being around them but they might not be prepared to deal with that person touching them. So, I only allow people to directly interact with a reactive puppy when the puppy is giving them a green light. And as soon as the puppy shows discomfort, the interaction stops.
You should probably also look for puppy classes, if they're being offered right now. I would talk with the trainer(s) beforehand to explain that your puppy is reactive and you might need to modify some activities to handle that. And that might mean that you arrive early the first night of class and let her explore the area without other people around. Or maybe you even go explore the area and people watch from a distance outside the training building a few times before the first class, so she'll be more familiar with the environment. That will allow you to work up to going in the building with her and seeing other people around. That way she won't be overwhelmed with the environment and
new people and other puppies and anything else that might suddenly seem overwhelming when she's feeling unsure and stressed.
Try not to get discouraged. Depending on the puppy, it can take a long time to work through it and I'm sure it will be more challenging during the pandemic.