We are greatly astonished by such claims that wrong great imams of Islam and undermine our principles of faith. The founder of the Hanafi School of jurisprudence, Imam Abu Hanifah, was a great faqih and scholar. He was born in the year AH 80, during the lifetime of some of the younger Companions (may Allah be pleased with them) and saw Anas ibn Malik when he came to them in Kufa. He narrated from ‘Ataa’ ibn Abi Rabah, who was his greatest sheikh, from Ash-Shu`by, and from many others.

He was concerned with seeking reports and traveled for narrating them. As for fiqh (Islamic Jurisprudence) and examining and analyzing reports, he was the faqih par excellence. Imam Adh-Dhahabi said, “It would take two volumes to tell the story of his life, may Allah be pleased with him and have mercy on him.”

His school of jurisprudence is one of the four well-known and recognized schools of jurisprudence in Islam. With regard to the approach adopted by Imam Abu Hanifah, more specifically using opinion and qiyas (analogy), it is never meant to be maintaining opinions based on whims and desires. Rather, it is an opinion based on evidence and analogy, or following the general principles of Shari`ah.

As regards your question, Sheikh Ahmad Al-Rashid, a prominent Muslim scholar, stated,

the Hanafi School of jurisprudence is one of the most trustworthy and accepted schools of jurisprudence. It is, in fact, the oldest of the surviving four schools of jurisprudence. Abu Hanifah (AH 80–150) was one of the prominent scholars of fiqh. He was known for his piety and extensive knowledge. He had reached a high level of proficiency and expertise in juristic matters.
Imam Ash-Shafi`i said, “All people are dependent in fiqh on Abu Hanifah.” Up to the present time, there have been numerous scholars who followed and supported the Hanafi School of jurisprudence.
however, some scholars criticized this school, accusing it of insufficient reliance on Hadith and of excessive use of logical reasoning. This criticism did not start a few years ago, but many centuries ago.
the famous judge and Maliki scholar Al-Qadi `Iyad (d. AH 544) said, “Admittedly, he [Abu Hanifah] had a very strong mind for considering matters, reasoning, and making astute comparisons. He was a very brilliant and preeminent thinker in matters of fiqh. However, he was not the same in Hadith, nor was his knowledge broad or extensive enough to make him independent in that field. He is not mentioned in most books of Hadith. The two sahih (authentic) compilations never quote a single word from him.”

Most of the criticism that was levied against him was about his relying upon ijtihad (personal reasoning) instead of acting upon Hadith. Some even accused him of rejecting sahih hadiths. One of the most prominent scholars who made this accusation was Al-Khatib Al-Baghdadi (d. AH 463).

Scholars have responded to these criticisms and declared them to be untrue. They demonstrated that Abu Hanifah would always follow Hadith whenever he found a hadith to be sahih. They cite statements made by Abu Hanifah on this matter. They quoted him as saying, “If a hadith from Prophet Muhammad (peace and blessings be upon him) reaches us, we will not accept anything else, but we will act upon the hadith.”

One time he was asked about what a man must wear when going to Hajj or `Umrah if he does not find the proper clothes. He was asked in that case, “Would you act contrary to the Prophet (peace and blessings be upon him)?” He replied, “May Allah curse whoever acts contrary to [the way of] the Prophet (peace and blessings be upon him). Through him [the Prophet], Allah blessed us and saved us.”

his student, Zafar, said, “Do not listen to what his detractors say. Abu Hanifah and his companions did not say anything but that which was in accordance with the Qur’an, the Sunnah, and authentic narrations Then, after that, they would use analogy to build upon these sources.”

Abu Yusuf, Abu Hanifah’s leading student, said, “I never saw anyone better than Abu Hanifah in Hadith commentary and in understanding the subtle meanings found in the Hadith. He had greater insight than I do in determining the authenticity of the Hadith.”

In truth, Abu Hanifah was the same as the other preeminent scholars of fiqh. He would use a hadith if he deemed it authentic enough to use as evidence. It is unimaginable that he would simply ignore a hadith and give preference to his own opinion instead.

If we come across an opinion of Abu Hanifah — or any of the other preeminent scholars of fiqh — that differs from the Hadith of the Prophet (peace and blessings be upon him), we must excuse him and consider the possibility that either he did not know the hadith or the hadith did not reach him through an authentic chain of transmission. It is worth remembering that compilation of the Sunnah was not as complete during the lifetime of Abu Hanifah as it was during the lifetime of the scholars who came after him.

I would like to conclude with something that Ibn Khaldun said,

How could it be possible that the preeminent faqih Abu Hanifah was ignorant of the Sunnah? How could he be ignorant while his preeminence in fiqh is an admitted fact? And how could it be that the majority of scholars took knowledge from him? In fact, the only thing that Al-Qadi `Iyad was saying about Abu Hanifah was that he did not reach the degree of knowledge in Hadith that scholars like Malik and Ahmad ibn Hanbal reached, for they were preeminent scholars in both fiqh and Hadith. These prominent people have the right to our good opinion.”