I get trying to get an extra pick in a trade down, and then take the guy you would have taken at #9, but if trading down prevents you from getting him, is the extra pick worth it?
If they have him targeted at #9, just take him at #9. I like Jawaan Taylor OT better though, but TJ Hockenson has far fewer red flags than any of the receivers, and he would provide a nice boost to the offense.
Didn't Seattle try to get cute in 2002 when they wanted Daniel Graham TE? They trade down and took Jeremy Stephens TE at #28, because New England took Graham at #21.