DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates (By similarity). Component of RNA polymerase II which synthesizes mRNA precursors and many functional non-coding RNAs (Probable). Pol II is the central component of the basal RNA polymerase II transcription machinery (By similarity). It is composed of mobile elements that move relative to each other (By similarity). RPB9 is part of the upper jaw surrounding the central large cleft and thought to grab the incoming DNA template (By similarity). Recruits ints-6, a component of the Integrator complex to PIWI-interacting RNA (piRNA) genes, to mediate Integrator complex-dependent cleavage of 3' ends of nascent transcripts upon RNA Pol II backtracking to terminate transcription and generate piRNA precursors (PubMed:33533030). Promotes the biogenesis of secondary 22G-siRNAs (a class of 22 nucleotide siRNAs that possess a triphosphorylated guanine residue at the 5'-end) (PubMed:33533030). Involved in gene silencing mediated by a class of 21 nucleotide piRNAs that possess a uracil residue at the 5'-end (also called 21U-RNAs) and guide the Piwi protein prg-1 to its DNA targets for silencing (PubMed:33533030). Plays a role in small RNA-directed transgenerational epigenetic inheritance (also called RNAe) over several generations (PubMed:33533030). Not required for the transgenerational inheritance of exogenous small interfering RNAs (RNAi) (PubMed:33533030). May play a role in the silencing of the DNA transposable elements from the DNA transposon families, Chapaev-2 and CEMUDR1 (PubMed:33533030). Component of the RNA polymerase II (Pol II) complex consisting of 12 subunits. Expressed in the soma and in the germline. Belongs to the archaeal RpoM/eukaryotic RPA12/RPB9/RPC11 RNA polymerase family.