I think it's been a pretty common practice to overstate height in a lot of professional sports for quite some time. Certainly you have to question some of the listed heights in the NBA. It doesn't bother me as much as people flat out lying about their age though.
The NBA is the biggest example for that ,they use their height while they are wearing shoes and approximate any quarter inch into an additional one(i,e if you are measured 6'4.25 you are listed 6'5) ,some players wear shoes that add more than 2 inches to their height ,I remember a player who was measured 6'7,5 without shoes listed 6'10
That said in football clubs measures players height and they do pretty accurate job most of the time specially when signing a new player ,I remember a German club found a player they are signing has listed himself 9cm taller than he is
Nobody lies about their age , Why would they ?
To be fair at the age of 17 your real age can be medically detected from simple procedures like panoramic x-ray on teeth to MRI's etc ,there is actually a real chance he doesn't lie about his age ,either that or Lazio are extremely stupid
I've seen a lot of guys who looked way older than their age ,though admittedly not like him