Prueba esto:
Código SQL
[-]
with subconsulta as (
SELECT C.Id_cliente,Nombre,Iden,Cupo,COUNT(*) as Tclient FROM ab_sucursal S
INNER JOIN ab_cliente C ON S.Id_cliente=C.Id_cliente
WHERE S.Id_user= :Id_user_B GROUP BY Iden)
select count(*)
from subconsulta
o también esto
Código SQL
[-]
select count(*)
from (SELECT C.Id_cliente,Nombre,Iden,Cupo,COUNT(*) as Tclient
FROM ab_sucursal S
INNER JOIN ab_cliente C ON S.Id_cliente=C.Id_cliente
WHERE S.Id_user= :Id_user_B GROUP BY Iden) subconsulta