Is it acceptable to attend a course or talk purely to gain knowledge (to get closeness to Allah) even if one does not share the same ‘aqeedah as the one presenting the course?

Yes, there is nothing wrong with this, as long as you know the correct ‘aqeeda and the talk or course will not affect your ‘aqeeda in a negative way. Allah tells us in the Qur’an,

“Help you one another in Al-Birr and At-Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression. And fear Allâh. Verily, Allâh is Severe in punishment.”[1]

Allah knows best.

References: 

[1] Surah al-Ma’idah, 5:2