I read this: The earlier leaks for the regular Galaxy S9 had shown the single-core score as 3648, while the multi-core score was reflected as 8894
I get nowhere near these scores: 1868 vs 6194
I just ran it on my S9 Plus and got 3733 single-core and 8957 multi-core. Have you got any other apps running? Try restarting the phone / closing all recent apps.