Вы можете использовать groupby
и unstack
df = pd.DataFrame({'ID': [1001,1001,1001,2001,2001], 'Key': ['K', 'C', 'D', 'K', 'C'], 'Value': [1,2,3,1,2],
'Object': [4,7,9,19,10]})
df = df.groupby(['ID', 'Key']).sum().unstack()
df.columns = df.columns.map('{0[0]}-{0[1]}'.format)
df = df.reset_index()
print(df)
ID Value-C Value-D Value-K Object-C Object-D Object-K
0 1001 2.0 3.0 1.0 7.0 9.0 4.0
1 2001 2.0 NaN 1.0 10.0 NaN 19.0