the topic title says it all. My son captured during a visit to the local library with the 85 mm f/1.4 AIS Nikkor set wide open (Nikon F4).
The image has been published many times also on magazine front covers so there is no doubt the 85 AIS is "sharp enough" ...
In common with the longer 105 mm f/2.5 Nikkor, both lenses do well at the wider apertures. True, you are not getting the pinnacle of their performance here but do consider what you use such lenses for at that settings anyway. You'll get plenty of sharpness and in both cases, a nice and creamy background.
The 85/1.4 can flare a bit when the subject is strongly backlit so ensure you use the longest possible hood that won't create vignetting. The successor AFD 85 mm f/1.4 Nikkor had less flare and kept the attractive bokeh wide open. The latest incarnation, AFS 85 mm f/1.4 Nikkor G has higher contrast and less flare thanks to its nano coatings.