You can get a client_id by registering the application in your connection settings on Twitch. The client id doesn’t really make much of a difference at the moment, but it’s a good idea to register and use it to future-proof the application better.
Even though you can do all the needed API queries immediately, it will still take time.
The best way would be to show a loading screen or a placeholder image until loaded. If possible, caching the page and/or images will help as well.