[4] Ilhan made his first professional start in a league game at the age of 16 years and 331 days, where he scored his first goal in a 1–4 loss against Albirex Niigata Singapore on 15 August 2019.
[5] Ilhan scored his third goal for the club in a heavy 4–1 defeat at the hands of Hougang United in the Young Lions' opening match of the 2020 Singapore Premier League season.
[7] Ilhan scored the first goal of the Young Lions' 2021 Singapore Premier League season, helping his team to a 3–3 draw against Balestier Khalsa.
[9] In total, Ilhan has grabbed 13 goals in 33 games, a better strike rate than his older brothers, striker-turned-defender Irfan (eight in 43) and forward Ikhsan (10 in 52), managed during their time in the league.
[16] Ilhan notched his first career hat-trick in his sixth game for the club, which included an outrageous bicycle kick that opened the scoring for Albirex.
[19] On 12 December 2022, it was announced that Ilhan had signed for Belgian First Division B club Deinze and will join up with his new team after the conclusion of the 2022 AFF Championship.
On 23 September 2023, Ilhan made his first appearance for the club in a U21 Reserves Pro League match where he scored a goal against Lommel U21 in a 4–2 home win.
Ilhan made his debut for the first team on 19 January 2024, coming on as a substitute for hat-trick hero Lennart Mertens in a 4–0 league win over Lierse.
During the 2024–25 Thai League Cup round of 32 fixtures on 30 October against Bangkok, Ilhan recorded a brace of assist which open up the goal scoring account in the 17th minute for Chananan Pombuppha.
Ilhan plays as an attacking midfielder, noted for his footwork, coordination and composure as cited by Singapore football legend, Noh Alam Shah.
[34] Ilhan is close friend with Indonesian national team footballer, Marselino Ferdinan during his time in Belgium and the duo would often meet one another on their off duty.