I struggled a bit with filling Hikaru's star meter myself at first. Make sure you pay the guard at the tv station so that you can see Hikaru there as well, overwise you won't be able to see all his scenes and get into a relationship. If money is a problem, you can get your bribe money back starting may by talking to the guard at the cinema and doing his quest after you have gained access to the tv station.
Hope this helps!