I agree with all of the point already made. What helped me the most was reading a book provided to me by the recruiter, from the hiring manager once I got the job (The Little SAS Book: A Primer, Fifth Edition https://www.amazon.com/dp/1612903436/ref=cm_sw_r_cp_apa_i_UJTpCb6HWH35C). Between this, online training from SAS (many are free), and Googleing, I was surprised on how quickly I could function at a competent level. Reading existing programs from others also helps a lot as well, since it might be more applicable than the random examples on the internet. Good luck!
Sounds like you are going to take the job, but the best book you can buy is The Little SAS Book. I have been a SAS developer for about 5 years now and still pull this guy out whenever something random comes up that I can't remember. Very well written and organized like a true reference guide rather than a textbook.
Look up SAS Essentials I & SAS Essentials II on the internet, both good resources for learning SAS.
Also, check out 'The Little SAS Book: A Primer' 4th or 5th edition. That book really helped me when I started in my programming position using SAS. Book on Amazon
support.sas.com/training If you have a little experience or none at all using SAS, this is a great place to start.
SAS e-learning Great place for e-learning modules using SAS.
In terms of how long it should take really depends on you and how fast you can pick up the concepts in SAS. I've been working in my SAS programming role (Biotech/Oncology) and I still learn something new everyday. It's a fun language to use once you get the hang of it and can do some cool things with it too. If you have any questions, feel free to PM me and I will try to get to them as soon as I can.
Hope this helps!! :)
The little SAS book is pretty good. Seconding /u/Euphoric_Journey .. youtube is pretty much your goto place. SAS community will be of great help for intermediate to advanced stuff.