He could, but traditionally the court is suppoaed to have seven Justices. He respects that did not want to be seen as trying to stack it. Unfortunately Republicans have no intention of giving the slightest fuck, were already stacking the court, and will likely continue doing so. If you ask me, I think Biden shouldve stacked it
If you had told me ten years ago that one day “°I will report you to doge” would be a valid sentence and a real threat, I wouldve died