Hi,
The T9 class came with two cab widths and with three types of tender. It appears that you have the wide cab version (with superheater) and a watercart tender.
I need to go into a bit of history. Firstly, the T9s were superheated between 1922 and 1929. Then after grouping in 1923, a number were transferred to the SECR and LBSCR sections to provide competent four coupled express locos. Only superheated locos were transferred and they were paired with 6 wheel tenders due to small turntables. Tenders with 14 foot wheelbase went with locos to the SECR and 13 foot tenders went with locos to the LBSCR. For whatever reason (which might have simply been the cycle of general repairs providing the opportunity to fit a superheated boiler), a high proportion of the 15 wide cab locos acquired 6 wheel tenders.
This left the following with watercarts:
302 - E302 to 5/1932, Bulleid green livery 1/1941
305 - E305 to 2/1933, Maunsell green & Bulleid lettering 8/1940
337 - dual braked to 2/1933, E337 to 4/1933, black livery after 3/1941
338 - dual braked to 10/1934, E338 to 11/1932, black livery after 3/1941
This is very simplistic, I haven't dealt with the fitting of snifting valves, the height of the capuchon on the stove pipe chimney and plates to the tender coal rails. You will need to find photos.
My source book is LSWR Locomotives, the Drummond classes by Don Bradley ISBN 0 906867 42 8. There are other books.
Bill