/u/BRIStoneman and I once posted a small book list on Late Anglo-Saxon England before in: Could somebody recommend me some books on England 850-1066?, but I'm afraid you might need more specialized book list for your research.

It is also worth noting that early 9th century (between the death of King Offa of Mercia in 796 and the ascendance of King Alfred of Wessex) has generally been a kind of gap between earlier and later in traditional Anglo-Saxon historiography.

In addition to the very basic Higham, Nicholas J. & Martin J. Ryan (eds.). The Anglo-Saxon World, New Haven: Yale UP, 2013, missing unfortunately in the linked thread above, I hope you might find them interesting, as shown below:

• Crick, Julia & Elisabeth van Houts (eds.). A Social History of England, 900–1200. Cambridge: Cambridge UP, 2012.
• Cubitt, Catherine. Anglo-Saxon Church Councils, c. 650-c. 850 London: Leicester UP, 1995.
• Foot, Sarah. Monastic Life in Anglo-Saxon England, c. 600-900. Cambridge: Cambridge UP, 2006.
• The further reading list in Richard Huscroft, Making England, 796-1042, London: Routledge, 2018 might also be useful for the departure point for your research, though the main focus of the books is political one.