This may be a general question and if the answer is it depends then please let me know what information might be needed. 

Clients (Married couple, he's retired, she still works) own and have lived in the same SFR on 25 acres since 1986, bought it for $78K.

He recently had about 9 acres of it subdivided out and is putting it on the market. 

Based on location and recent sales of land in that area he could get upwards of $250K for it. 

Would he have to pay capital gains tax on the sale? 

In doing some research what I found is that if he also sells off the home and rest of the land within 2 years then he'd qualify for the $500K Capital Gains Exception since it would count as 1 transaction to the IRS because he'd have sold off his primary residence. However if he doesn't sell the home and rest of the land within 2 years then he would have to pay capital gains tax on the sale of the 9 acres. 

Can any verify or clarify this? 
I know he needs a CPA but wanting to do a little research first so I can speak intelligently to him about what he should expect to hear from the CPA. 

Thanks