For applicants coming from the US, the usual order is that the sponsor receives approval in 3-4 months (many are approved right away, but if there are questions it takes longer. In my case it required 3.5 months for sponsor approval, which made me happy because of our particular circumstances.) Generally, the US visa offices do not send an acknowledgment of receipt. Often the next thing you hear is from the visa office requesting your passport (or copies of the passport pages).
Using the open data project the numbers for Buffalo, applications for spouses indicate that 20% of applications are completed in 5 months, 50% of applications are completed in 8 months and 80% of applications are completed in 12 months (these are not identical to the values posted on the website, because I have used the "spouses" category not the "spouses and children" category).
So, that would suggest 8 months would be a very fast response time (3 months for sponsor plus 5 months for applicant) with 11 months being more typical (the 50% number). If there are any issues, you should be prepared for something closer to 15 months.