I recently noticed what appears to be Magnolia scale on my tree, which was planted Spring of 2019. I did some research and read that the best time to spray
is late summer, around September, when the insects are more vulnerable to sprays at that particular time in their life cycle. If this is Magnolia Scale, I read that neem oil is a natural option, which I always prefer. Does anyone have a particular brand of neem oil and a recipe they found effective? I may not wait until late summer because I don't want the scale to spread and further harm the tree. I suppose I could spray it now and then again in September.

I also noticed some of the leaves appeared to have what looked like black dirt on them. I don't know if that's from the scale.

Thanks in advance for any advice.

The black stuff is a sooty mold. It is feeding on the remaining sugar/nectar left by the feeding insects.
Scale has a very short life cycle, most are three to five weeks not months. You just have to be careful about any treatment being exposed to full sun. This will likely burn plant tissue.
When I enlarged some of your images I seem to see the skins of aphids. They are more likely to attack the new soft branch tips and more likely to be responsible for the black sooty mold.
Once you spray and control the insects, the sooty mold will wipe off with a damp paper towel.

Thanks Bill for your great advice!

Your are welcome and I wish you all the best!