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HIP 65426 hosts a young giant planet that has become the first exoplanetdirectly imaged with JWST. Using time-series photometry from the TransitingExoplanet Survey Satellite (TESS), we classify HIP 65426 as a high-frequency$\delta$ Scuti pulsator with a possible large frequency separation of $\Delta\nu =$7.23$\pm$0.02 cycles day$^{-1}$. We check the TESS data for pulsationtiming variations and use the nondetection to estimate a 95% dynamical massupper limit of 12.8 Mjup for HIP 65426 b. We also identify a low-frequencyregion of signal that we interpret as stellar latitudinal differential rotationwith two rapid periods of 7.85$\pm$0.08 hr and 6.67$\pm$0.04 hr. We use ourTESS rotation periods together with published values of radius and $v \sin{i}$to jointly measure the inclination of HIP 65426 to$i_{\star}=105_{-9}^{+7}$$^\circ$. Our stellar inclination is consistent withthe orbital inclination of HIP 65426 b ($108_{-3}^{+6}$$^{\circ}$) at the$68\%$ percent level based on our orbit fit using published relativeastrometry. The lack of significant evidence for spin-orbit misalignment in theHIP 65426 system supports an emerging trend consistent with preferentialalignment between imaged long-period giant planets and their host stars.

HIP 65426 is a High-Frequency Delta Scuti Pulsator in Plausible Spin-Orbit Alignment with its Directly Imaged Exoplanet