This answer is yes, but the scale function is limited.
Take a look at
http://nocash.emubase.de/gbatek.htm#lcdobjoamattributes
with the reg of
OBJ Attribute 0 (R/W)
you should enable the Rotation/Scaling Flag
with the reg of
OBJ Attribute 1 (R/W)
you should set a number 0~31 for bit 9-13, which determines the 'Scaling Parameters'
for the 'Scaling Parameters', here is the description:
Location of Rotation/Scaling Parameters in OAM
Four 16bit parameters (PA,PB,PC,PD) are required to define a complete group of Rotation/Scaling data. These are spread across OAM as such:
1st Group - PA=07000006, PB=0700000E, PC=07000016, PD=0700001E
2nd Group - PA=07000026, PB=0700002E, PC=07000036, PD=0700003E
You should check the BG scaling for the meanings of PA,PB,PC,PD.
e.g. if PA=0x100, PB=0, PC=0, PD=0x100, the picture shows what it is.
if PA=0x80, PB=0, PC=0, PD=0x80, the size of picture would be half of the original(32x32 -> 16x16)
So, there are only 32 scaling groups, that is what limited.