Take a photo with the chain on the largest front and largest rear (cross-chained)
And a photo with the chain on the smallest front and smallest rear (cross-chained).

My guess is the chain will be hanging loose on the small-small combo.

Did you use a "quick link" when installing the chain? If yes, then just split the quick link, cut off a few more links, and put it back together.

If no. What is that, 8s? You can usually push out a pin about 90% of the way, split the chain, join, and push the pin back in. If you used a "link pin", don't re-use that one.

As far as lubing, I usually wait a couple hundred miles, or until the first good rain storm.