Crear tabla - Error de SQL:ORA-00905:palabra clave faltante

En lugar de double puedes intentar usar NUMBER (precision, scale) . Así que prueba algo como esto:

CREATE TABLE Player(
Plyr_ID int NOT NULL PRIMARY KEY, 
Plyr_Fname NVARCHAR2(20),
Plyr_Sname NVARCHAR2(20),
Plyr_DOB date,
Plyr_Height NUMBER(7,2),    --Change as per your requirement.
Plyr_Weight NUMBER(7,2),
Plyr_position NVARCHAR2(20),
Plyr_experience int,
Team_ID INT NOT NULL,
CONSTRAINT fk_Team FOREIGN KEY (Team_ID) references Team(Team_ID)

);

NOTA :double precision son tipos de datos compatibles con ANSI, mientras que NUMBER son tipos de datos integrados de Oracle

Entonces, si lo desea, puede apegarse al doble usando precisión como:

CREATE TABLE Player(
Plyr_ID int NOT NULL PRIMARY KEY, 
Plyr_Fname NVARCHAR2(20),
Plyr_Sname NVARCHAR2(20),
Plyr_DOB date,
Plyr_Height DOUBLE PRECISION,
Plyr_Weight DOUBLE PRECISION,
Plyr_position NVARCHAR2(20),
Plyr_experience int,
Team_ID INT NOT NULL,
CONSTRAINT fk_Team FOREIGN KEY (Team_ID) references Team(Team_ID)
);