There are a couple of crates you may use to approach this.
To perform the HTTP requests you could use the reqwest, library. It's been in development for a while and seems fairly stable.
Just a few days ago surf (see also here) was released by the rust async ergonomics working group. If you're feeling fancy you can have a go at that - although I'm not certain how async functions would work in rocket.
You could have a look at gotham too, which may piece together more nicely with async functions, as it's async itself, however I haven't used it yet.
To parse the data you obtain from these APIs you could use serde_json which together with serde can parse JSON into structs, or allows you to directly analyze a JSON value.
For performing both requests in parallel you can either use async or just launch two threads: see this example.
Now, in case you're just getting started with rust I would recommend to try out doing any one of these things in isolation first. Trying to do everything at once may be overwhelming at first. I think a good task for a beginner may be to attempt to make the requests, using the reqwest library and then parse them using serde_json.
Best,
ambiso
Edit:
note that surf and async-std might just not be ready enough yet.