9.9 gms % is indeed a low Hb during pregnancy. Now it has been proved that injectable iron has no advantage over oral iron time wise. It requires 3 weeks for the iron to get converted into haemoglobin. If there is any pathology in your stomach and/or intestines which is hampering the absorption of iron, or you cannot ingest iron due to vomiting, then only you think of injectable iron. Your increased stores of iron will supply iron to baby also whose iron stores will be enriched. Otherwise, after birth, baby has no source of iron. Haemoglobin is made of two components - haem and globin. Haem requires iron while globin requires proteins. Therefore, please consume good amount of proteins (meat, eggs, pulses, legumes, etc.) also. Only iron will not help. In the diet, include cilantro, jaggery, green pepper (chillies), lentil and green leafy vegetables which are good sources of iron. I hope you have got a good guidance. :)