Sent my first lead nine days ago and heard nothing

Follow up, once, and make it about the lead rather than the money. Something like "did the one on the corner turn out to be anything? I've got another that looks similar and want to know if I'm reading these right." That gets you feedback and it puts the second lead on the table without handing it over.

Nine days isn't much. Reaching an owner on a house like that can take three weeks if the mailing address is stale.

The part I'd fix before the second lead goes out is the nothing in writing. Not because he's dishonest, you have no reason to think that. It's that $1,000 to $2,500 with no definition means he decides later, alone. Two paragraphs in an email is enough: what a lead is, how long a submitted address stays yours, and the fee. Ask him to reply confirming. If he won't put a number and a window in an email, you've learned something worth more than this deal.

Also go back and read that notice on the door, or at least photograph it from the sidewalk. What it says changes the whole picture of who that owner is and how much time they have.