There's a lot to consider in picking any spot to hunt, all covered in detail elsewhere. There's an ongoing debate about morning vs evening and if hunting mornings is worthwhile. Several collar-ed deer studies indicate less movement in the morning compared to afternoons, but it's still better than mid-day. I'm just referring to research I've read. Your experience may be different. How you can approach the field will be key, and what you know about wind direction will be tested. I always assume the deer are in the field feeding in the morning. That sorta limits approach. Again, your experience may be something different.
Soybeans are good until yellowing which, I think is just an indicator of timing. This is about the time acorns start dropping....if there are any. And if there are, your opportunities in the soybean field will be more limited. So far as acorns are concerned, some years are good. Others not so much. The other thing about soybeans I think would be helpful to know is if they are full season or double crop beans. In Harriosnburg, VA double crop beans (usually planted following wheat or barley) are planted as last as July 15th. While day length determines the soybean growth stage, those late planted beans might stay green and palatable much later into the calendar year.
Just some thing you might want to consider as you make your stand decisions.