Hadith About the Virtue of the Basmalah
Question

The hadith (narration) about the virtue of the Basmalah (saying in the name of Allah) and that it protects against the 19 guards of Hell, is it authentic?
Praise be to Allah.This report was mentioned by al-Qurtubi in al-Jami’ li Ahkam al-Quran (1/92) and Ibn Katheer in his Tafseer (exegesis) (1/18), narrated from Wakee’ from al-A’mash from Abu Wail from Ibn Mas’ood (may Allah be pleased with him); it is the words of Ibn Mas’ood, not of the Prophet (peace and blessings of Allah be upon him). 
This isnad (chain of narration) is saheeh (authentic) from Wakee’ to Ibn Mas’ood. 
Although al-A’mash is mudallis, what he narrated from those with whom he spent a great deal of time and narrated a great deal from them, such as Ibraheem al-Nakha’i and Abu Wail, may be accepted. 
Al-Dhahabi said in his biography of al-A’mash in Mizan al-I’tidal (2/224): 
He is mudallis (i.e., gives false impressions concerning the narration of the hadith, using ambiguous words to give the impression that he heard it directly from his Shaykh when that is not the case), and sometimes he narrates in this manner from a weak narrator without realising it. When he says haddathana [he told us], there is no problem with that, but when he says ‘an [narrating from], there is the possibility of tadlees except in the case of narration from the shuyookh from whom he narrated a great deal, such as Ibraheem, Abu Wail [in the printed version it says “Ibn Abi Wail” but this is an error; the word “Ibn” is a mistake] and Abu Salih al-Samman. His narration from these shaykhs is to be understood as meaning that he heard directly from them and there is no interruption in the chain. End quote.
But there remains the issue of the narrators who come after Wakee’. Al-Qurtubi and Ibn Katheer do not mention the isnad in its entirety, and perhaps it is because of this that al-‘Allamah Ahmad Shakir omitted it from his abridgement of Ibn Katheer’s Tafseer which is entitled ‘Umdat al-Tafseer, in the introduction to which (1/11) he stated that he omitted every weak or problematic hadith. 
But al-Suyooti attributed it in al-Durr al-Manthoor (1/26) to Wakee’, and Imam Wakee’ ibn al-Jarrah wrote a well-known Tafseer.  
See: al-Majma’ al-Muassis by al-Hafiz Ibn Hajar (p. 113) 
If this is proven, then the isnad is saheeh, and the report from Ibn Mas’ood (may Allah be pleased with him) is saheeh. 
And Allah knows best.