His Medal Index Card is on Ancestry - Victory Medal, British War Medal and 1915 Star.
Commonwealth War Graves Commission has an entry:
Private 18259 Robert Hamilton
9th Bn, Royal Irish Fusiliers
Died 19th April 1918
Son of Mary Hamilton, of Kilmore East, Ballinode, Monaghan. Enlisted March,1915.
Can't see his service record? But then some 65% of WW1 Service Records were destroyed in a WW2 bombing raid?!